For your .270, it's Rldr-22 for me. Lots of guys swear by H-4831 and/or H-4350. Also, you might try IMR-7828 although I haven't used it myself. Sorry, can't help with the .243.
I would recommend that you copy a page of reloading data from a manual for each of your rifles. Carry these in your wallet and refer top them each time you go into a store selling reloading gear/supplies. That's what I did when I needed powder to load my 9 mm.
Bear in Fairbanks

Last edited by Bear_in_Fairbanks; 04/07/14.
"Unless you're the lead dog, the scenery never changes."
Amazingly, I've lived long enough to see a President who is worse than Carter.
And finally,
Gun control means using two hands.