My personal fav for .243 is 4000MR, very consistent and accurate. IMR4350 is a close second. You can cover .243, .270 and .30-06 with the same powder, something in the IMR4350 burn rate range. the .23 and .308 will need something a bit faster, down around IMR4895 or W748 burn speed range. IMR 4064 is the closest thing you could get to a universal for all. There are loads listed for all but the .223, its far too slow for .223. I personally would use IMR4895 and IMR4350 in your situation.
I've had good results with RL19, but recently started loading and using the new Hodgdon Superformance powder. It only has uses in a limited number of cartridges but lists the Barnes 80 gr. TTSX at 3,600 fps at the muzzle which is astonishing. Even more astonishing is that it's actually 3,630 out of my BDL and shoots under 1/2" at 100 yards. I won't be loading anything else in that caliber.
My personal favorite for the .243 is IMR4350.
WW760 was another one that I liked using but it gave me inconsistent velocities in cold weather.
I have used IMR4064 for lighter bullets (87/90gr and under) and RL-19 for 100gr loads too, but IMR4350 was the best all-around performer in the couple .243s that I've owned.