Re: which 7mm
Since you have an RUM action I think that solves it. You can't do any better performance wise on your action than a 7mm RUM. I have two of those and six 7mm STW's and love both. But for your action with 180-190 grain bullets The RUM case would be good. The STW not that much less with performance and better on barrels. The STW can be shot without a break by most but the RUM starts to punch a bit if that makes any difference. Lots of things to consider.
Predictions are difficult, especially when they involve the future