This probably the most ideal, If you look at all the bigger 3gun matches this year, Most will have you doing a anaerobic event (running, climbing over objects) just prior to jumping on a rifle with Long shots, which causes the heart rate to spike up. The better you can control this the less "bounce" you have to worry about in your scope.
Not to knock Taran, because the guy is a BEAST! but he does tend to stay away from matches that are more of a physical challenge. (ie. BRM3G, RM3G, and Ironman.)
To the OP, its really not a easy question, I say continue the program your on and start adding in muscle flexibly training. More times then not your going to find yourself in less then optimal shooting positions, being able to get in, stay relaxed, and able to get out of them will shave a lot of time. Also a good breathing exercise would be helpful, I see to many people get to excited during movement and tend to want to breath through their mouths, this is a bad thing as this makes the heart Spike even faster, so being able to breath through your nose even while sprinting is what I suggest. If your trying to control recoil by "muscling" it, then you should probably work on technique instead.
This.
I don't multi, but I've tried ACTS, which may be even more physical and contorted. Strength is good, but only if accompanied by agility and endurance. If you can't actually fire a wep during your workout, at least work in some dry firing or magazine changes when you're at, or near, peak heart rate.