I have a pair of larger RX2 which were originally single wired from a Marantz PM6003. Sounded OK.
I then had them bi-wired from an Audiolab 8200A. Sounded better but that's the amp.
They were also tried bi-wired from a Cyrus 8XPD QX. That's where I heard their limitations.
The RX1 has a smaller mid/bass driver. WHF seems to think smaller MA speakers should be single wired to retain "coherance".
They are also 6 ohm so will run a bit louder but with a touch more distortion than 8 ohm speakers (which is what I prefer).
I'm a firm believer that any speaker should be demo tested with the amps you're considering.
My RX2 are now successfully partnered with an RX center from a Marantz HD AV amp. As I've noticed a few other posters pointing you towards a PM6004, perhaps try that and the new PM6005.