I've found an easy way to do this with minimum fuss and get maximum reaction from your audience: Get a case of 1.4 mines and several racks for mines ONLY. Put the mines in two stations on either side of your main show, angled out slightly if you have the room. (only a few degrees, not sideways).
Fuse together whatever 1.4 product you think makes sense for the type of music you're using. You can do some really rough time calcs and try to have several segments fused on independent strings to sort of mirror the time of whatever your soundtrack is.
Leave lots of time between song segments if you can stomach it. I'm talking like 7-10 seconds.
Set up your cues so the last 5 or 6 (or however many song segments you have) are at the end or beginning of your buttons (like 24 through 32 or something). Those cues should each be wired to your fused segments as well as mines on each side. Then all the cues 1 through whatever should just be on mines.
Start your show with cue 24 (or the first cue tied to a fuse) as soon as the music starts. Then, depending on how many mines you have, you can hit mine cues on any big musical beat you want. The effect is immediate and if your finger is fast enough, it'll give the illusion that the whole show is computerized from just a few perfectly synced mines.
Each time the soundtrack changes, move your finger to the lower buttons and hit the next fused chain cue. The crowd will remember all the mines going off right in sync with the music, and the rest of the pyro in the air will be seem like it was scripted.
Have fun!