Matt, I wouldnt chance it man. TTB beams are cheapo.
Also why mess around with the D28 any more? GO D35.
Brett and I built the jigs and a set of 3" cut and turned D35 beams. We are working on the second set now (for his Ex, first set going in my BII)
The TTB beams bend easier then you think, however you are right in assuming the drop brackets for the axle pivot and radius arm bend first (thank goodness)
But you can get a set of beams so cheap why even risk doing all that work to a bent one?
ONly way to tell for sure is to measure yours up against a known good beam, can be hard to do because of their funky shape.......
I am going to be running a 5" eibach coil with the Duff 2" drop brackets, 3" cut and turned beam, Skyjacker radius arms, and rancho 9000's. The bump stops will be moved down a little to avoid any problems, and I may need limiting straps to keep my axles from leaving the diff (ARB = no c clip). 13-14" travel is common on a setup like this with non heim radius arms.......