I'd recommend a mandatory cooldown for each missile.
Something tells me that blasting 8 of these one after another is not going to be really good.
Well the things don't lag all that much except if you get hit by them (in which case you'd be dead anyways) so something like 1 missile every 3-4 seconds would be possible, only once you're out of missiles you'd need to get an ammo crate or something otherwise it would be too much. I recon something like 4 missiles max would be enough.
I can fire 4 2x scaled missiles simultaneously and watch them hit a target and I'll only lag a little bit, surprisingly.
