Squash help please

I have 2 uchiki kuri plants and 2 butternut. There's a couple of fruits on the uchiki kuri that look like they might go the distance but the butternut are only just producing flowers. Will they set fruit in time? Is there a cutoff date when I should just cut my losses and let the plant concentrate on the fruits already set? I've found generally that my squash and melon plants although looking healthy and seeming to have plenty of bees hovering around them seem to have had trouble pollenating. I have been going out to try and hand pollinate but not much luck even so. I've been going out in the morning but the female flowers never seem to want to open! Does anyone have any tips for how to encourage pollonation? (Probably for next year now haha) Thanks