I was looking at increasing the rate at which the Pirates launch too,
But found with maps, i could create custom maps with lots of pirate bases, one i made had 12, haha, boy was i asking for it!!
Anyway, i dont know if it would make them launch quicker, but it certainly gives you more bases to eliminate. 
You can try it if you like, but i'm not certain its what you want. But i thought i would offer it as an idea, if it helps.

-Teal