Re: 6.5 Creedmoor and others...
You already have it figured out sir. You made the "tradeoff" for the 123 / 130gr bullets and avoided having to deep seat the heavy bullets, which would have brought you down right into the range of the slightly lesser case capacity of the Creedmore. The CM and 140gr bullets lose less case capacity to deep seating of heavy bullets, thus it and the .260 come pretty close to each other in this use case.
Pretty much pick one and smile. The lapua does have very high quality ammo you can purchase, so that may make some difference. I am not sure the .260 has anything but good old hunting ammo. If you reload then that "advantage" is nullified.
Have a good one,