Those things'll work. I kind of favor the Hornady 180-grain JHP-XTP meself, though I don't have a G20 right now. I've got two pals who've owned and carried 10mm Glocks for better than a decade now, and both love the things. One is a Wyoming rancher who raises cattle in wolf and bear territory [too close to Yellowstone] and traded in his S&W M29 44 mag on a Glock 20 when the things first came out. He tends toward a heavier bullet [230s and 240s] though I don't know if he's actually dropped a bear with one- I know he has used his Glock on injured cows and bison. And has no complaints, or he'd be carrying something else. The other guy is an ex-cop, whose old dept carries the Glock 17/19. Now more on his own than previously, he's happier with the Glock 29, and he likes the Hornady 180s as well.
If I was to be carrying one again, I expect I'd start out with either Winchester 175-gr STHPs or the Hornady loads, either from the factory or from Cor-Bon.
Your the second person recommending the silvertip 175gr. I am leaning toward the corbon powerball for my arena....any good or bad on that ?