I bought these nylon 1/4 - 20 bolts that have a sort of thumb nerled (spelling) top to them (slotted for a regular screwdriver but has the extended height head that is nerled (spelling again) to be turned by fingers to make them finger tight. That's what I use and they get tight enough not to come out and loose enough to remove easily. This seems to be the best way to tighten these nylon bolts so they are not over torqued. I bought them at the big WRAM RC show in NY last year. A bag of 50 of them cost like 5 bucks or so. Well worth the investment. Same vendor sells the hex-head servo screws, 1/2 inch and 7/16 inch long. They are great.

DS.