Not a pumpkin expert... but just a few thoughts and more questions for you. If you have plenty of bees, why not just leave it to them? Could you be damaging the females when pollinating? I'm sure you're not, but just throwing that out there.

I don't have any experience with trellises, but I know pumpkins like them just fine, so that shouldn't be a problem.

You already said you're getting a soil test and that sounds like a good plan. Who knows, it could just be nature's way to get rid of one pumpkin and put more energy in another.

Another random that you might already know... your pumpkins are all members of different families so they can't pollinate with each other. Jackolanterns are pepo, butternuts are moschata and hubbards are maxima. I'll bet you already knew that, but just wanted to make sure you weren't trying to cross pollinate them :).

I am being very gentle and most I have pollinated have gone on to become nice fruits...Using the approach of pulling the petals off the male and using as a paintbrush....about 8am.....I think I can fine tune that but my husband said he just the more pollinated the better the production that number of future seeds both determines size and viability.

It is interesting on one vine, the first hubbard (about baseball size) is dying but the second is growing like no tomorrow (bigger than a softball) and the third is dying at less than a ping pong ball..........

Well this is a learning year and we will be delighted if one hubbard makes it as it was planted as a trap crop and we have already pulled some / destroyed borers in them.

No...I am using the "right" flowers for the pollination. Our first pumpkin female fell off early but the 2nd one may bloom tomorrow..........Lord Knows there are 15-20 new MALE blooms every morning....I am hoping to get one of those as well. WE wound up with 7 healthy butternuts that are just seasoning now on the vines (starting to turn tan)

So much to learn about all of these plants.!

Someone on another post mentioned that when it is too hot the fruits may abort in the early stages. I just had a nice new one come up but we have had a very temperate week with more to come. The previous weeks and NIGHTS had been warm with nights in the upper 70s but this week they are in the 60s.

Sadly I had no males because pickleworms got in all the maturing blooms.......well......I went ahead and crossed with two different C pepo and we will see what happens......I really remember crossing my first one with a zucchini which is also c pepo and it took. We will see. I figure better to try than nothing. I can't imagine any male butternut flowers with a half mile of me.

Actually I found a study where c pepo x c moschata produced edible fruit in several crosses. Figured it was worth a try but not holding my breath.

As mentioned earlier, squash and pumpkins do fine on a trellis. However, the vines send out roots at the nodes if soil is available to them thus the vine could support more fruit. On a trellis, the vine is restricted to only the main stem. If you have any stress due to hot weather, insects or disease the extra root systems go a long way to support the plant and fruit.

Absolutely a valid point. I am thinking next year of running my vines along the bed for about 3-4 feet before I run them up a trellis to give that added margin of safety. With limited room, squash could overtake us without trellising them but that gives some margin of safety and greater rooting.