i think best answer to this if you dont want to manually fire off verdict.storm etc is to get him on the dummy and follow the rotation without storm o verdict and estimate over time the most likley/often time 3 power is up, and do a average this way you will probably get good results and sometimes average.

ive done this with my enhancement shaman with MW, i need 5 stacks but i have been on the dummy working out the best time mw is usually ready so put lb in the rotation where its more likley to be able to fire off. i have tried with and without stop casting and both results are very much the same.

p.s if you change gear the proc times will change so you will have to start all over again, so gear up and spend good half hour getting a good accurate estimation.

i got a mix class group and handling ds,mw, and others from my team is tough to keep tabs on, it would work with i set them off manually with jamba proc but tbh i cant always keep tabs on wtf going on at times its better for me to do above.

maybe you guys can try it, so far i have got very good results.