Lee Shaver is the Pedersoli US service smith. Might contact him to see about sending it to him to have the trigger worked on, just to try and keep the thing warranted.
Real gunsmiths like Steve Baldwin, and Eron Ahmer would be good bets as well. With Baldwin being closer to you in Oklahoma than Ahmer in Colorado.
Yes MVA bases will fit the factory drilled holes, and they will include the metric threaded screws.
