I'll second what John said, you dont need the trex. The benefit of 777 is its cleanliness compared to black or pyro, so there is no sense adding unneccesary goop.
Hodgdons recommend just a wonderlubed wad but 777 burns slightly faster and hotter and on advice from a great number of experienced American shooters just lubing the ball with alox is ideal and about as clean as you can get with m/l other than a nitro conversion.
They make these revolvers with the front sight a bit long because the only adjustment the user can do to otherwise fixed sights is shortening it.
But as said dont start filing until you have got your load sorted and getting consistant groups.
“If a cricketer, for instance, suddenly decided to go into a school and batter a lot of people to death with a cricket bat, which he could do very easily, I mean, are you going to ban cricket bats?” :- Prince Philip said after Dunblane