ok, ball ends should be tight enough that you have to fight to get them into place, and off again. if its too loose, maybe youre using the wrong ends. pick up the right ones at your hobby shop, theyre only a few bucks for a pack.

i havent had any experience with those drift tires, but i would suggest just heating up the plastic rings in a toaster oven for a few minutes. take them out and they should stretch over the wheel pretty easily. but dont get too rammy with it, you dont want to stretch the rings so much they dont fit tightly anymore. you could also try putting the tires in the freezer for about an hour beforehand.