Seriously, I use titegroup a lot in 9mm and .40, and you can easily double charge even in those small cases. With your large case, it raises all kinds of alarms about reduced charges. I've seen ringed barrels from wads producing unpredictable pressure curves, so it could be an expensive experiment to try using wads.
For the 460 S&W Magnum, Hodgdon shows a starting load of 15gr of titegroup under a 325gr lead bullet at 48000 PSI.
I would ask them why there is no smaller load listed before inventing one. I like titegroup, but it has never impressed me as a powder to just experiment with "off the charts."
Can't you just load up some .45 colt cases using 7gr titegroup and 180gr lead bullets and shoot those in the 460 magnum for plinkers? Hodgdon lists that. Am I missing something?