Your spacing looks for a DSS LNBF and not a StarChoice LNBF with a StarChoice dish. I have not measured the two, but the StarChoice LNBF may be closer to the arm?[/http://www.satelliteguys.us/threads/313471-Salvaged-Star-Choice-dish-tried-for-FTA]
You are right, Larry1, dilligent observer... Indeed, I used the wrong LNBF, as I misplaced the original 2 LNBF's and had to use - just for a demo - anything which would fit in the bar. But, for finding the right spot for replacement, I used aluminum flat with plastic sheet - see my post,
http://www.satelliteguys.us/threads/313471-Salvaged-Star-Choice-dish-tried-for-FTA. I noticed, that this alum-plastic "jig" does not fit all dishes, as the LNBS' faces are at various angles to the bar - and I had to bend the alum. flat in the vice to fit it to particular dish - which was a chore. The cardboard template can adjust to any angle, as it is being held by C-clamp to the side walls of bar, not to the top wall. Cheers, polgyver