I used Red Dot for Cowboy loads before switching to Trail Boss. Unique, a bit, before that.
Part of the cowboy drill is about filling the case as much as possible (no risk of double-charging) without creating a stout load... and Trail Boss is good for that.
Generally, sights will be sorta-kinda close with whatever mid-range load you use from any reputable recommended source. Then you can tweak from there if necessary.
Very occasionally you might have to file the front sight a bit... or maybe even bend it a bit... but over the course of 10-12 cowboy pistols I've not ever had to do any of that...
-Chris
