We've gone a slightly different way in terms of how we are making back trusses work with Ubolts/Leaf springs.
When we are putting back trusses on one of our Fabbed 9" housings for a leaf sprung application, we've got a piece that we use to notch the back truss and leave a gap between the housing and the truss where the U-Bolts pass through. It is essentially a rectangle with coped ends to match the axle tube, that has 2 90* bends.
The part we have is coped for our 3.5" axle tubes, but could be easily modified with a grinder to work for a factory 9" axle housing and back truss.
I'll see if I can get a pic for you guys, its not something we have on the website but if you call or email the sales office when you are ordering the back truss we can add a couple of those in for you.
In terms of a top truss, with leaf springs, really the only way you can do it is have it a short truss from the top of the pumpkin and tie into the leaf spring perch on the inboard side. You could if you were feeling ambitious build truss that extends from the leaf perch outward, but that would be overkill if you want my $0.02.