im running the hi pinion in the front. when i drilled my holes, i put the third on, and drilled through. kept em pretty straight, but when i tapped the holes annd put the studs in the were kinda off, so i just tapped em with a hammer and it fits great. sounds like you got everything else pretty much buttoned up. dont know why you notched the perch, unless youre running lo pinion. if you got any pther q's let me know.