Cutting out pieces of the firewall lip

[Kats66Pny]

Gave in and went and bought some hammer and dollies to straighten the lip since it got all warped from removing the old cowl. Now I'm trying to figure out where and how much to cut out.

Yellow areas - What needs cut out?

Green - I'm trying to figure out where the larger section on the lip is suppose to start on the other side. :shrug

 

[Midlife]

I'd consider a brass backing plate and welding those holes up in the yellowed area; the brass won't accept the weld, but keeps the puddle onto the steel lip. That lip will all be covered up anyway with the cowl piece (right?), so you only need a lip such that you can plug-weld the cowl on top of it.