I have 2 RCF NX12 SMA's and I have used one and two with the AxeFXII. My opinion is that these are probably the best of the middle of the pack in terms of FRFR. I think they are outstanding for cover bands since they need to be as neutral as possible to reflect the diverse sounds coming out of the AxeFX. If I were you, I'd definitely get one and test it out within the return period. Make sure you are comfortable with lack of "in the room" sound that you most likely get from your 65. In isolation you might not think anything of it but if you set the FRFR right next to your 65 and A/B test them, you'll probably notice it. However, the versatility will probably outweigh the lack of "in the room" sound since you've already mentioned the weight of your current rig and the need to perform covers. Lastly, perform your own QC on the speaker. It sounds like a substantial number of these speakers had QC issues that will be audible. Thankfully, neither of mine exhibited any of the issues and it sounds like RCF has either solved the QC issues or is getting better at addressing them.
PS get a bag for it. The handle is inadequate... nice that it's there but it's not balanced or comfortable. RCF sells a bag but there are other options.
