The .243 is fairly easy to load, but I use the slower powders in that caliber and I've never used 4350. I like 4831 and Reloder 22, although I do have one recipe for IMR 4895.
The point is that everyone reloads that caliber differently and your rifle will certainly find one combination that it likes. My best advise would be to try a ladder test with the powder you've selected and use the combination that gives the best accuracy in your rifle.
Dan Newberry explains it as well as anyone, but the idea is to find the optimal for your rifle. You've already chosen the bullet, primer, brass and powder so the only task left is to find that specific powder weight that will let your rifle shine. Then all that's left to do is start exploring seating depth and tweaking the load.
Good luck on your quest. Lots of folks find that the .243 Winchester is very satisfying and easy to load for.