Understand this... I don't presently own a 40cal and I don't want to represent my self as any type of 40 expert...
But I have shot pistol competition, and I know you want to eliminate all potential problems at the outset. Loading your own ammo should be used to eliminate shortcuts used by the giant factories, but if you don't pay attention to all the details, then handloading can just as easily end up introducing errors of your own making. This is the source of my concern.
• One of the issues with TG is the excessive heat, which can lead to barrel leading when shooting lead. Leading can make your accuracy totally disappear within a very short span.
• Another is "case fill". TG is a VERY dense powder and case fill can be an issue. Once a load was chosen, I'd want to do extensive testing over a chrono to make sure that velocities were constant, regardless of the physical position of the ammo.
All the best.