I've had good luck fixing bent crashes using a wooden-headed hammer & a ride. I lay the ride upside down on a soft surface & hammer the crash against it. Once progress slows, I'll pop the crash inside out & go again. A few times through the cycle usually gets it pretty close.
I've done this multiple times.
My 2 cents -
You can lay a drum hoop atop the cymbal & use the lug holes to mark out a pattern.
You can use a hole-saw in a cordless drill & that works fine but you'll be stuck with holes the size of whatever saw you used.
I like use a step bit. With this, you...
I got a big pile of heads & some nifty Tama push-button wingnut replacements from Santa, & sneaked & bought myself another busted Paiste (18" Heavy Crash). A little Dremel time & she's good to go!
I also got a bit o' cash, promptly converted to a 22" Sonor Force 2000 bass drum (which of course...