I would actually consider a smaller range top and portable induction burners for extra burners during the ten percent. An advantage of this might also be that you could set up a completely separate extra cooking zone, allowing two cooks to work on burners at the same time.

I had some similar concerns when I was planning. I needed to be able to cook for several dozen (though not for several days running) and have half a dozen people working in the kitchen without hindrance.

• Wide aisles are essential.
• More work stations are more useful than longer counters, though having at least four feet to work in is preferable to less
• No one likes working in the corner, especially when everyone else is in a more social position.
• Storage doesn't have to be in the kitchen, but the pots, spices, and other staples do.
• It's amazing what will fit in an ordinary fridge.
• Portable appliances are your friends.
• Have all self service stuff outside the kitchen workflow

If your 10% (larger version of the family) like chilled beverages, sodas, beer, etc., then definitely have an ancillary fridge well removed from the kitchen, and have a station near it with cups, napkins, recycling, trash, openers, etc. You can also put fruit and other snacks there.

Any chance you could get the coffee and bar out of the kitchen too? Put out pitchers of water and ice buckets and maybe a bar fridge (can be unplugged when the 10% aren't there for the fixin's. Do you have a buffet in the dining room or somewhere that you can make into a full on breakfast station? Not just the coffee, but also a microwave, toaster, etc., that can hide when they're gone.

Train them all that the kitchen is not a place to wash. If they're used to bringing outdoor gunk into the kitchen rather than traipsing through the house, you can buy an inexpensive garden sink that hooks up to a hose and put a box of cheap bar towels next to it and a basket for the used ones.

As to the kitchen proper, I wouldn't put the sinks side by side. That puts everyone too clustered together with no room to actually work. Two people can work at one sink, but they need a couple feet of counter space and turn space and elbow room between them and the next pair. If you were thinking that that would give you two large single basins rather than a single double bowl sink for handwashing, a better solution is a couple of dishpans in a large single bowl sink. That's what I do when I have dozens to dinner.

Current dishwashers take a couple of hours to run. Having two would definitely cut down on kitchen labor, since one won't hold a single meal's dishes for that many. When I have dozens to dinner, the cooking stuff goes in the DW (I only have the one), and we hand wash the fancy stuff using the two dishpans in the sink method, and it works great.

Having a large prep sink, however, is a good idea. You may find that you use it plenty even when it's just the two of you. It'll be more useful for the 10% visit to have it located in a separate station. That doesn't have to be a huge distance from the clean-up sink, and, in fact, can be more useful if it's pretty close, but they really should be separated so that pot washing and prep can happen at the same time, and that elbow...

I recommend buying the book on Amazon "kitchen design with cooking in mind" It talks about all of this in the best way I have ever seen.

One more thing to consider is a convenient place for coolers on a floor that won't be ruined by some dripping water. If folks are going to all be bringing things, you can end up with 8 coolers on the floor in the kitchen, taking up all the floor space by the table. So a mudroom, pantry, porch, or staging area with counters for coolers and probably a utility sink might be really nice to have.

Our complex has a common facility kitchen that regularly hosts large groups cooking and eating together. Things that work:

* one 24" dishwasher, but it's a commercial one that does a cycle in 2 minutes. it's been going for 12 years with no issues. needs storage room for special trays for glasses, etc. everyone LOVES this - especially men

* all sinks and appliances have counter space separating them

* large island that is used for prep and serving - this is used much more than the perimeter counters

* one range, one cooktop, and one wall oven

* 4 sinks - 1 prep in island, 2 standard sinks, one utility sink - only the prep and one of the standard sinks are regularly used

* laminate counter on the island has NOT held up to 12 years' worth of traffic

* island has a hole for cords to plug into outlet below for slow cookers, hot plates, etc. for serving

Thank you for your thoughtful responses! So much information I hadn't considered before. Thanks for taking your time to respond. Mulling all this over...