RE: Weight vs. Power
They will both kick about the same and performance should be about the same too. The 7mm shoots a little flatter and lighter bullet so I would use that to determine between the two. If you hunt out west and expect longer shots go with the mag. Otherwise it's a toss up so don't worry about it. Just find the rifle you want and then you can go from there.
I have a 7mm but thing either is fine for 99% of hunters.