Congrats on your USFA Flat Top Targets. They are beautifully made pistols but I cannot afford one. Therefore, I settled on the working cowboy's cousin of the Flat Top from Uberti with 7,5" barrel, BP frame in .45 Colt some 8 years back. The dealer added a complete overhaul of the action and I fitted Gripmaker's PU grips with the longhorn to fill the right hand. Being an average shooter only on a good & sunny day I can easily hit head size targets 100 yards away with these old fashioned sights using a two-handed stance. So, the accuracy potentials is there.
Not to steal your thread but to add my experience with a similar pistol.
Long Johns Wolf