John,
Silhouette is generally 40 or 60 rounds per match. But generally there are 2 matches, and practice, so 120+ shots at a club is probably the norm. I have a SCBA tank, so refill is not an issue, and it can be topped off between, practice, and matches. Naturally it is desirable to have less refills to have one less thing to do.
The targets are from 20 - 40 yards. The 20 yard target is a chicken, and I guess about as big as a quarter. That size is not so challenging from a rest, but offhand it needs precision.
Likewise the ram at 40 yards is a bugger if the velocity is changing. So the shot velocity curve adds another hurdle that can be pretty frustration.