Not all rules related but:-

30mm to 45 yards - great
25mm to 40 yards - great
10mm from 8 yards - 20 would be good, even better as a kneeler.
Mini kills, oversized & undersized targets are all good ideas.
I guess if the course is 'too hard' it could put people off, or will it, maybe they want the challenge & can't wait to get back to try again, it's a tough middle ground to find by course setters & I appreciate the work taken to make a good course a great course.

Up the peg shots are a good idea and having seen Gabriel grow a fair bit in the short time he's been shooting there can be issues for smaller youngsters, he has never taken a shot on a lane in a position not allowed & a few times his pellet has gone straight in the dirt because he couldn't get high enough OR he just couldn't see the kill zone, having said that I guess you could always come off the peg with an elbow, knee or leg. Case in point was a lane @ SHS yesterday (around lane 5 somewhere), there was a prone shot around 45 yards, you had to shoot between the juncture of two high tree branches in a V shape to a target even further behind, the lad in the group ahead of us was a very small junior & could not see over the V to even see the target so took the shot about a foot from the peg, we didn't hear any of the group suggest coming 'off peg' either (the last thing you think of, I also felt rotten for thinking of it too late to say anything), anyway he missed the kill as he wasn't supported by the peg.

I find that targets around 9 yards tend to catch a lot out as it can be half a mil diff than an 8 yarder, elevated, long & short shots, also thin the heard, tunnel or tube shots especially with the rear end covered over (cheers Simmmo)with braches then leaves make quite a tough target to see but I thought it's based loosely on 'hunting' in which case that scenario would happen 'out in the field' (also it's a fun shot )

Not telling people how to suck egg's so sorry if it sounds it but if you have trouble seeing close up shots this may help, when looking through the scope move the kill zone in the field of view from the centre to one of the outside edges, it will become a lot less blurry or get your team mates to 'flap the target string'.

Atb