flinchlock hunter,

I'm not certain that you can readily change the PA hunter over to double set triggers...the inletting is not the same on those as it is with the Hawken and Renegade models. I'm not sure why you would want a double set other than you don't like the factory trigger pull which is kind of stiff. Well...there's a reason for that. Pennsylvania is one of (if not the only) state that has a late muzzleloader season that is flintlock ignition only. T/C designed that gun with an enlarged trigger guard and a stiffer trigger pull to accomadate hunters wearing gloves because the flintlock season opens on Dec. 26th. which is usually pretty darn cold in the part of Pa. that I live in.
I would suggest that if your not comfortable with doing the work yourself that you take your lock to a competent gunsmith and have him polish and smooth all of the bearing surfaces until you get a nice smooth break, that's IF and only IF you don't like it the way it is...

BPS