I'm a big fan of using 1) butted spokes and 2) a gauge heavier butted for the right rear. Usually I use the same spokes for front, left rear and right rear of fix gear wheel with little dish. Cassette wheels always go a gauge heavier. I've been doing this 40 years. It works. Using the same spokes left and right on dished rear wheels means either the right side is pushing too tight, running the risk of popping spoke heads, breaking the hub flange or cracking the nipple seats on the rim or running the left side spokes too loose, chasing tighten and true for the life of the wheel and perhaps breaking spokes from uneven tensions as some unwind. If you build the wheel perfect - it works. But I would much rather have a wheel that does just fine 5% tighter or looser than "ideal" and runs trouble free.