Nice work, you should try taking a fine grinding stone or lapping compound to the valve face if you havn't already. I use the hard white delrin cup seals meant for a spider but they had the same leak as yours until I polished the seat. The original seal was a softer material(feels a bit rubbery when poked with a fingernail) and the one I have left never leaked even before polishing the seat.
For some anti-chop protection I put the stock bolts back in my rainmakers and run the LPR at ~60psi. I've got 2 of marty's black delrin bolts and one white delrin bolt, but they have a bigger hole and sharper edge on them than the stock bolt. I've never chopped a ball(tough field paint) with the stock bolt but have a couple times with the delrin bolts.