"Any suggestions for drills that might help me pick which will suit me best in competition among the 3?"
You may have to shoot ea. in a Match to really find out which works best for you?
When you start out and sometimes after you need to learn the importance of "Setting up the 1st Shot". Don't worry about getting the pistol out of the holster and up fast. What you need to do is lock your eye foucs on the exact spot on the tgt. you are going to aim/shoot at, then
always bring the sights up to your eyes. then concentrate on the 3-Secrets of shooting, "Sight alignment, sight picture and tribber control".
If you get that 1st shot it's much more likely that the rest of the Stage or string will go wel for you.
IDPA is fairly heavily time-weighted so always have the question of "If I had taken an extra 1/2 to 1 sec. on that Stage would it have kept me from getting that many 1 or 3 PD's?"
Shoot for best accuracy 1st, sped will almost naturally come in its own time.
While this article/link mostly concerns the Classifier ther are good solid shootig tips in it:
http://www.ccidpa.org/clastips.html
Scrounge some used IDPA targets and put ca. 1" red dots in the center of the head box and center of the 8" COM scoring ring. This will help habituat you to unconciously center the sights dead center. No need to try doing it fast smoothness and good hits are what counts plus you'll develope confidence in your ability to get thehits at different distances. Then try with multiple targets in aa linear array and place one round on ea. as slow as you need to go to get the best hits you can. Eventually space them at 3 different distances.
Also a dry-practice routing both from the ready and holster can work wonders as a comliment to live fire practice.