No matter how hard you try, you just can’t cut fine wood work with a pair of Kleins, and make it look good. This is exactly why I exclude cutting patching and painting on my proposals. The template is a good idea but you are still on the hook if it comes out wrong, even if it’s not your fault. What works well for me is I give them a cut-in box and a plate to use as a template, if they screw that up than they can blame Raco and Hubbell.