I think that is the right descision with the front end. It just gets so annoying when you have to keep redoing things!!
Re. the de-dion, depends on your facilities a bit. If i were working at my old place, the way we'd have done it there would be to have used the spare old surface table, which we used to tack weld stuff down to. I would scribe out the positions of the outer hub flanges on the surface plate, then weld some "dummy hub flanges" to the surface table, measuring and re-measuring to make sure they were in the right places. I'd brace them too with gussets on the outer edges. Then just bolt your outer hub flanges to these solid mounts and fabricate the rest to fit in between.
I don't have a surface table now so I make do with a large lump of 1/2" mild steel plate laid on the floor, which is accurate enough………….or was until I chopped it up for something else, need a new one now!
To be honest, a lump of old RSJ from the scrapyard, as long as you can check that it's straight with a straightedge, would do the job for building the axle, just weld the dummy flanges to that.
Projects wise for me, the 7 clone is progressing slowly, rolling chassis now with bodywork in place, sorting the engine at the mo (Xe 16v) by the end of the month should have engine + box in, only challenge for this bit is machining up the concentric clutch release cyl mounting for the type 9 'box, nothing very drastic!
Still awaiting the 2 speed box for the grasser so that's dragging along as well!
I don't have a surface table that big either, it would be great for this kind of thing! I was thinking about making up a dedicated jig out of box section so I just bolt the axle bits up to it, and then weld it all in place. It'd be good to have a repeatable process when making it as the axle is a precision part, and if I break it it'd be easy to make another. I'd have to make sure that the jig is very precise though, and won't change shape when I do the welding. an RSJ sounds like it's do the job much better than box section though, I think I'll hunt one out.
I'm still not 100% sure about stock sierra width. it does make things easy, but it may be worth widening the track slightly more. It's best to do it at this stage, I guess. more food for thought.