Ron,
I think your questions were on 45-90, didn't see another here on the 45-120. But to answer some of your questions, you can rent a reamer for less than $50 including shipping from 4D or Elk Ridge. I had mine done by a local smith, cost was $135 including the rented reamer, but you can do your own by hand, there are a few members here that have done them, Richard and Joe to name a couple.
As for filler, put enough powder in it and you won't need any filler!!
Even using AA's data for 5744, you won't need filler, it works excellent as it is, I only loaded a bit above what they list at 31kcup, but I didn't see a problem working on up. I didn't have QuickLoad at the time, but using Tyler's and Richard's loads would be a perfect place to start from, just depends on what bullet you want to use, the 405gr Rem isn't a good choice as Tyler found out, the 350gr Hornady is another matter tho, it's a great bullet, the 400gr Speer would be a fairly good one in the same weight range as the 405gr Rem.
There's data on AmmoGuide from a shorter barrel, 500gr at 2100fps in a 24" barrel, I don't know what pressure he was running it at tho, Tyler's loads were kept at a predicted 40kpsi maximum to prevent damage to the underlug, the 500S&W has known issues with underlug setback at 50kpsi and the slightly bigger case head. I can run some QL3.5 predictions for you based on the shorter barrel to give you and idea of what to expect.
Tim
