Shorting an axle and measuring for axles?

I'm ready to get my axle built and realised I may be about to screw this up big time.

My axle is a ford 9" fabricated housing with a spool.

First should I put the 3rd member in the housing and line up the rear yoke to the trans output? How much off set do I want side to side?

I have almost zero room from the side of the tire to the mini tub. I guess I need to lower the car over the wheels and make dam sure the tire is centered side to side in the tub or I'm screwed.

I also have concerns that I'll not be able to get the wheel off the studs once its sucked up in the wheel well. I guess worse case I'll have to drop the back of the springs, shocks and brake line? I could use a long brake line but that only solves one issue.

The rear end shop is super busy and not returning my calls so the're no help. I'll be calling strange tomorrow to see how they want me to get the measurements but I figured I'd ask you folks as well.

Anything that stands out to you that I'm not thinking about?
I'm gonna have a lot tied up in this axle so I cant afford to screw this up.

Tha is for the help and advice.