I'm currently shooting a 66" recurve with a 25" riser and short limbs. Is it feasible to change to a 23" riser and use medium limbs? I understand the longer the limb the more "forgiving" the shot. Ta.
Exactly this. Many years ago I had a Greenhorn with this very set-up and couldn't get a sight mark at 20 yds. Apart from that it was fine.
It was very borderline, so depending on your face shape and anchor etc you may well be OK. I've recently shot a fellow club member's 23" riser Horizon with no problems at 20 yds, so its worth trying one out.