Suds,
I am in the same process for a Winchester Featherweight 7mm WSM that I have. I followed the loads in the Sierra manual for 140 and 160 grain BTSP and HPBT using IMR 4350 and H4350 EXT with really good success. Now I'm experimenting with Hornady 139 gr. BTSP. I called Hornady with the very same question, as the recent Hornady load manual doesn't specify which is better - these, R19, or R22.
Hornady suggested that I go with a load that provided a good load density (how full the case was left) and a moderate burn rate. That ended up being R19. I have the test loads made, but haven't shot the them yet. Hope this helps.
Matt