assembly questions

The rollers are fine they have always been shorter than the raceway

But your complete 3-4 synchronizer assembly does not look A833 to me.,
and most of all, your third gear overhangs the hub-stop on the mainshaft, that's not right either.
I don't know what's going on there, and I have built dozens of A833s and hundreds of Manual transmissions in general. I'll let my brain sizzle on it for a while, and see what what drops out.
I'd like to see an edge view of the slider, and
one of the thrust flange part of the mainshaft. I have seen pieces of those flanges broken off , and poorly welded back together.