I'd tend to stick with the .532/.515 belted mags and not the .532/.540 nonbelted ubermags; the 1917 action is strong but it's not the newest and most consistent in terms of steel quality.
I'd especially be wary of Eddystones vs. Rem or Winnie versions, since the Eddystones have a statistically significantly greater likelihood of having been heat-treated a bit too hot (not like the '03, tho) and having had the barrel overtorqued upon installation. The combination of these two issues is such that the receiver ring can develop microcracks when you pull the old barrel off. It doesn't happen all the time, but it is a known issue with Eddys.
If at all possible - pay the $$ to have the receiver magnafluxed before you reuse it.