I use a lot of
#6 countersunk, and (mostly) #8 countersunk, a few pan heads, of both sizes, some tinnerman (CS) washers. Usually half-inch and three-fourths lengths will do for everything. I buy my assortments through Hare aviation, in Texas. For everything outside, I use stainless Phillips head, but there are pros and cons (of course) on these.
RV-10 Co-built (sold)
RV-8A Maintained and flown (Sold)
RV-6A Bought and Flying (N177RV)
IO360, 180HP/CS, AFS 5600T, D10A, G650, G430, G327, ADS-B, VIZ385
Very Happy Contributor
Based at KCLW (Clearwater, FL)