haw far would you over power a set of speakers that are say 45w

My mids are rated for 40watts each. I'm giving them 75watts right now, and would not hesitate to give them 150watts. In generall I dont look at power ratings. I will give a speaker as much as I can and simply listen for warning signs. No distortion, no break up, no problem!

i'm giveing someone a set up and the amp is a pg 500.2 for the main speakers and he is 16yr old kid

set the gains for him and hide the gain dial on the amp.

this is probably not really relivant but would anyone know how to figure out how much power an amp puts out at any given point on the gain dial.
im just curious cuz i have my tweeters and mids set on 0 gain right now and they are still ridiculously loud