rp, I have one of the very first .243 Weatherby Vanguards, the same rifle as yours, but with a 22" bbl. My "standard" deer load is a 100 gr. Hornady SP over a charge of H-4831. I can get a bit higher velocity with IMR4350 but I still have a good amount of the original H-4831 on hand and use it when I can.
My best shooting 243 load only has a velocity of about 2700 fps but it kills our southern deer very well. Most of my lung shot deer run, full bore, about 40 yards and passout on their feet. In doing that, they die exactly like those I shoot with my bow, a .35 Rem, a .270, an -06, a 7mm Rem, etc IF I hit them the same. Have tried the partitions too but couldn't tell any difference with them either but partitions would be better with larger critters. So, remember that paper ballistics don't kill but holes in the right places do!
Considering the speed deer run and the distance (mine) typically travel before passing out on their feet, it's just a matter of 3 to 5 seconds before they drop. That's not instant unconsciousness and death but it's pretty close! And, for me, it is a rare deer that drops in its tracks with any caliber unless I hit the spinal cord.
I don't think you will be missing anything with your rifle and loads either. Hunt and enjoy it.