Rear Upper strut bar cut outs...

i'm soon gonna get a rear strut bar and i'm gonna have to cut the 2 areas for the bar to fit into my interior.... Does anyone have any advice on how to do this....?

if u can remove the actual part that u mount put that on first and then push against the capeting or whatever to find the mounting bracket, then use a razor blade or sumpin and cut the hole according to where the bracket is. at least that is what i did.