I think basically your rifle has told you what it likes. Also, remember that some rifles are more finicky than others, and even thought you've tried different bullets, with different powders, maybe you just have not found that magic load. There are guys here who swear by the TTSX, and that is they shoot through their 257s. The Vanguards are notorious for being super accurate, and if your rifle likes the TTSX, I'd tweak that load a little and find a place where you can shoot at 300-500 yds, so you know what that bullet is doing.