I would try both the MMP HPH24 and the Harvester Smooth short. Ive had good luck with both sabots and loaded OD with PT Golds is really close. Last time i shot them was with smokeless in the Harvester Smooth so i know they will handle hot loads just fine.
I dont know how TB ever got the groups he claims using the Crushrib/Pt Gold considering he says its bore is a tad large in the protoype he usually uses. I could push the the same combo down the bore of my Extreme 50 with 2 fingers and it hated them with any amount of powder. Its bore was a tad large too but the HPH-24 shot pretty good with the 260gr version and a bit better with the 300gr. The GoldDots did even better but they are a little larger OD.