Good to see you here again! I heard about your decision to drop the 300 Win Mag from layaway and go with the .243. A little easier on the shoulder and better for varmints, you will be pleased with its performance on deer sized critters and smaller I suspect.
To answer your question on the .243's performance on deer. My experience has been skewed towards the short range (150 yards and under). I personally have only killed one deer with the .243 out of a Weatherby Vanguard, quite an accurate rifle and a joy to shoot. The deer I shot was at about 50 yards, I shot and clipped the shoulder blade and destroyed the lungs and the deer ran about 40 yards or so. Upon examination, the bullet didn't penetrate much but damage was devastating. Because I wasn't happy with the bullet's performance I rid myself of this gun. I was shooting 100 grain PSP Winchester factory ammo. Conversely, a buddy of mine has killed over 24 deer with his 243 and none of them ran further than 40 yards. His longest shot was approximately 150 yards. At long range, I can't say what this caliber will do. However, I'd suggest the 95 grain Nosler Ballistic tips. You have a good BC and a heavy enough bullet to do fine at the longer ranges without breaking the bank. The 107 grain bullet may fly well out of your barrel so I'd load up a few and give them a try. If they fly just as well as the 95 grainers I'd go with the heavier bullet.
Good luck in your pursuits.
By the way, don't give up on your 25-06. If the thing still shoots well enough for you then I wouldn't consider it "shot out". If it isn't shooting well, consider getting a "take-off" barrel. Gunsmiths may have brand new factory barrels for under $50.00. You could even get a different caliber so long as it was a long action cartridge. This guy is up in your neck of the woods I think, check it out
He's got good prices on barrels and for a few extra bucks you can have it installed.