I'm not sure how the bins on the bottom are getting air.
Do the worms look happy?
If so then they probably are.

I built mine similarly. I have
1) Solid bucket - catches leachate, saves the carpet. I have to check and empty this periodically.
2) First worm bucket, holes drilled for drainage.
3) Two bucket "spacers". I cut the bottom 2/3 off two buckets to create a two bucket "lift" between the first worm bucket and the top bucket.
4) Top bucket. Placed when the bottom bucket has reached the point where it will come into contact with the bottom of the top bucket.

I feed fast. I feed slow. The worms seem to have been able to tolerate about 2 gallons at a time if they have somewhere to get away from the fresh ("fresh" being a relative term - normally it means aged a couple of weeks under the sink) food. Once the top bucket is filled to the top with food and enough bedding to keep odor down it could sit for a few weeks to a month before it gets worked down and there is actually room to add more fresh food.

Here is a link that might be useful: My bucket system

Worms thrive on neglect. They don't expect three square meals a day. I'm sure your feeding schedule is fine. I would add bedding with every feeding. Buckets are kinda small. I would have stuck with the bigger totes, but if the buckets are working, then they are working. They have got to be easier to handle than the totes were.

When I had my worms, I had two bins and one extra tray. One of my bins had the extra tray on it to encourage the worms to migrate up. When I harvested that bin, the harvested bin became the extra tray on the other bin. Whether you have 3 trays or 5 trays may not matter.

I would just keep doing what you are doing, except maybe not letting them go unfed for more than a couple of weeks at a time.

Plus not feeding them for a few weeks when they were being fed blenderized food every day is different than not feeding them for a few weeks when they were being fed whole pumpkins, un chopped brocolli stalks, corn cobs, sprouted potatoes, and dented apples. These things will continue to break down slowly over a period of months.

I actually have 3 stacks. Two are as I described the third is a curing or finishing stack with only two buckets, the catch bucket at the worm bucket. I do feed the curing stack making it more of a "fattening" stack :)

I also managed to sneak a two bucket system into the office. It doesn't get fed very often, but the vc is beautiful.

I've been running my system this way for a couple of years now and have had enough worms to set up four others for friends and family.

ozzz, I think it is important to realize there is virtually no limit to the ways people can vermiculture. Buckets, bins, tiered systems...they all work, and they all have their own limitations. I have four 30 gallon plastic tubs, and no two are exactly alike even though they operate with the same type of media (peat moss), and get fed twice a week. The choice of blended foods will vary somewhat, but other than that all things are similar.

My simple rule of thumb for this system is two, thirty gallon plastic tubs per household member will match the food scraps available for feeding. I do however supplement with garden scraps as needed. These scraps I keep in five gallon buckets in my shed. When I finish a bucket I bring in a new bucket, allow it to partially thaw, and chop the ingredients with a sharp shovel. This material will begin decomposing quickly and the bucket will need to be covered with a lid.

Unlike a lot of people, I have three basic rules for my indoor vermicompost bins: No holes, no lid, and I keep a light on 24/7.

morgan-3: not having a lid for your indoor bins, don't you get flying insect problems in summer?

"My simple rule of thumb for this system is two, thirty gallon plastic tubs per household member will match the food scraps available for feeding."

This seems like a lot of capacity per person. While my worms don't quite keep up, I'm at about 4 gallons per person. I think for my worms to keep up with our output, another stack might be sufficient. That would put me at about 30 gal capacity for 5 people. (No way would I be able to talk my wife into 150 gal capacity)

Do you have a large amount of scrap output - ie vegan or vegetarian diet? Significant amounts of paper or cardboard waste?

Nice thing about vermicomposting, there are about 1000 ways to do it 'right'.
Sometimes, I think we get overly concerned over the minutia trying to make things 'perfect'.
ozzz, I think what you are doing is just fine.

I love the stacked pickle bucket design! I've been looking for something I could put in my garage during the winter! Thanks for posting a link to your blog!

Things I like about the Patrick1969 bucket system:

Using pre-used buckets.
Looks like an air space was cut into the lids.
Aging buckets where "The remaining worms will be relocated to the more active buckets."
"bucket tops are cut off to make spacer rings." Really like that.
Do you find when seperating buckets that worms are on the outside of the inner buckets and have left castings?

When I lift off a bucket to check the lower level there are invariably worms hanging out of the holes in the sides of the top buckets. I have one stack that is so full of worms right now that when I lift it off, the side of the bucket looks like it has red stripes :)
There are castings all along the outside of the buckets as well where the worms have poked through the 1/8" holes and made their deposits.

Also, I changed up the order of one of my stacks. I started out with solid, habitat, spacer, spacer, habitat. The bottom habitat bucket continues to get worked over and the level sinks down. I was adding some bedding and scraping VC to build the VC level up the to next bucket mounding it up so it would make contact. For one of the stacks I decided to move a spacer from the middle to the top so it's: solid, habitat, spacer, habitat, spacer. This actually gives more room to add feedings on top and I don't have to mound the VC in the lower bucket. I do have to remember that the top "bucket" is just a spacer so I have to lift the second bucket down or I end up with unprocessed food everywhere - ew! :)

Here is a link that might be useful: Building the 5 bucket worm stack - video

Mainly it's a matter of assessing what is good worm habitat. You're looking to avoid extremes of temperature and too wet/dry, and you want to be alert to bad smells -- anaerobic bacteria. Otherwise, as long as the worms are eating and making compost you should be fine.

I do try and add cardboard at least weekly -- it's easy to keep a stack of those dividers used in liquor cartons, and tear one or two up into the bins. If it gets hot in summer it's worth checking in more often, because problems can develop quickly.