I have not hunted with or guided with that specific combo, but it will work just fine. Don't overthink it. Know your weapon and where it shoots and go kill your elk
I’ve shot a few critters with Federal’s 175 Fusion 7mm load. Seems to cause a little more blood shot than something like a partition, but still maintains decent retained weight. I’d imagine the 150gr might cause a little more blood shot, but dead is dead.
I’ve used the 140 Fusion out of a 280. I found that while it’s a bonded bullet, it performed more like a traditional cup and core. I had a couple fragment into 3-4 fairly large pieces on cow elk. Killed the elk but was not confidence inspiring as those large jagged fragments could have easily taken a different route and led to a rodeo.
The 150 7mm RM load is a little faster than the 140 280 load. So for me, I would be placing it broadside at close to moderate range. Further out it should do fine. I have seen several Alaskans speak highly of the 150 load out of a 270 Win. for Moose and Griz. I think the difference is the lower velocity.