I've been trying to hold off replying just because the responses have been so good I didn't want to do anything to put the brakes on the thread.
Having done a lot of reading on this forum and elsewhere, I know the responders include some of the most respected, experienced and knowledgeable aerobatics pilots around, and it's hard to say what a pleasure it is to have a forum like this with guys like you being willing to share your years of expertise, so thank you all very much.
Basically, all I have been doing to date is applying full in-spin rudder and holding the stick full aft, ailerons neutral, until applying opposite rudder, then waiting some time for the rotation to slow somewhat before guessing it was time to apply forward elevator. So now I know that last part, in particular, was wrong, and there's a lot of other fine, and not so fine, tuning to be done as well. All the comments about the timing, pitch control, rudder/elevator sequencing, in- and out-spin controls, the amount of time in which one can expect the rotation to end (with proper technique), and even the pre-spin setup, were all extremely helpful and enlightening -- not to mention the warnings on crossovers and spin training.
There sure is a lot going on in mastering comp spins, isn't there? Not sure I really needed things to get more complicated,

, but I guess it's better than remaining in the dark on the finer points.
I've had occasions where I did a 4 turn spin, then applied opposite rudder (only, initially) and became concerned when the rotation just seemed to continue for a while. On the other hand, I know Saber25 has a video where he does something like 11 spins in his -4 high in the Rockies. So I can only conclude the delay I experienced was due to poor technique, particularly with elevator application - which makes me feel even better about the ability of RVs to respond to anti-spin controls (while recognizing no two experimentals are the same and it wouldn't be a good idea for anyone without advanced spin training to try either a small or a large number of spins).