whitetailer,
Welcome. I shoot several accurate loads out of my Pro Hunter. 240gr XTPs are very accurate but hard to get down with supplied sabot. After the bore is fouled they load a bit easier. I just got me some .452 300gr XTPs to try and when I shoot them I will report. I'll probably try the 45/50 Crush Rib sabotsandsome 45/50 MMP HPH3P-EZ sabots to compare. 250gr Shockwaves also shoot good.

With all that said...my go to load (the one I will use tomorrow on the last day to hunt) will be the 275gr Parker BE. Very accurate!

As far as sighting in with a clean or fouled bore you should experiment with that. I use BH209 and I am sighted in with a clean bore. Every time I shoot at the range I load a parker and shoot my first shot from a squeaky clean bore just to verify. The remainder of the group shoots about 1" to the left of that first shot.