Check your arbor length. My Uberti needed a washer in front of the arbor. Otherwise you tilt the barrel up when you tighten the wedge. Defiantly the Tresso nipples are a necessity.
As for the original 'pimple on a flea' front sight - is it threaded or just press fit? Eventually I'll remove it & make a taller sight to raise the point of impact up around 8".