Skeet is a 20 yard target at best or closer, so a wide open choke is needed, mostly at the #8 station where 6 foot shots can happen.
Most use Skeet chokes but you can "Try" a Mod. if that is all you have, just don't think tou will hit 25 out the 1st time.
Trap is a different ball game. A mod choke to a I/C will work from the 16 back to the 20, while the Mod can be used back to the 24
for a wide open pattern.
Most shooters just screw in a FULL choke for everything from the
close 16 all the way back to the 27 handicap, where it is needed
for a better pattern on those long shots at around 50 yards or more.
Even though the full has a tighter pattern at the 16 yard line, it
is actually a better "Teaching" choke, to learn if you are putting
your pattern in the right "area". Anyone can get lucky with a
skeet or I/C choke................