I think I may have answered my own question via research.
I may be wrong with what I read/heard, but the 147 grain 9mm round might have a property I fear the most which is over penetration and also a tendency to not expand properly if it penetrates heavy clothing, where as the 115gr hits with a lot of force and the energy dissipates rapidly and tends to not over penetrate. Both are great rounds, the 124 might be the sweet spot for that round, but I am still going to err on the side of caution and stick with the 115grain JHP.
If I had been able to post this question in the EVO forum, I might have been able to get a clearer answer about cycling a EVO with the 147 grain subsonic, but I guess I'm not allowed to ask any ammo question in a specific gun forum, go figure.