Hey! So in the middle of a fight for example, if youre 90% spec. As soon as you hit 100% itll take a certain amount of time for 10% regen again. So about 1 second before that regen you use your first spec, then itll regen and you use your second. Very similar to double korasi specing back in pre-eoc. Usually they will have a timer etc in the middle of a fight so this can be acheivied, personally I think its alot of work for a double msb spec.
-Or you know, you could buy the mbow scroll XD