You'll need to make the new holes as close as possible to the stock ones. And in the same plane of course. But watch out because I made mine a little to close and had to trim the stock tabs to allow for the YJ spring eye to fit in there. Might not make sense now but it will if you look at it closely. I wanted the rear axle as far back as possible and having done it this way, I still need to drill the perch and move it back about 3/4" or so. Hope that helps
Cheers,
Steve

Cheers,
Steve