Hi Jim and all,
I'm going with the Railflex, good quality and very adjustable. Plus it's the factory "matched" binding that does deliver good results. This binding is the best all-around choice.
I considered the Free flex with the CP13 or other Tyrolia "race" plate. This would be ideal for me since it should improve grip and responsiveness compared to the Railflex. I would mount it 20mm forward to allow some versatility in binding position.
Maybe if I find a flat RX8 for me...
Cheers,