Can I build a diff myself, and anybody used this tool?

I may be getting ahead of myself as I've got other issues going with the car right now but I'm trying to plan some things out.

I've never touched a RWD diff before. I have a bare 741 housing, a new Truetrac diff and new 3.55 gears. I'll pick up the full install kit, and I should have everything.

I do already have a dial indicator with adjustable arm/mag base. Now if I have to buy a pinion depth tool, I'd probably just pay to have the thing done as it won't save enough money for me to go through the hassle. However, I saw this and have read a few good things about it:
http://www.summitracing.com/parts/rat-10007

Has anyone tried it? People that have assembled a diff and set up gears before, should I attempt this myself or just bite the bullet and pay the $250 to have it done?

As always, thanks in advance for your help and opinions.