^^Love mine mounted at 87 w/FKS using a Full Tilt w/ #10 tongue. It's the nimblest ski in the my quiver, and I use it in tight trees all the time. YMMV and all that. Think 88 might work okay but I would hesitate to have less tip in front of me. Doubt 86 would do it for me though.
Have you printed mount patterns yet? I ask because that really will determine where things line up. FWIW, I generally center the top two holes in the dynafit toepiece between the bottom two FKS holes. Because the RX 130 and TLT5 have a drastically different bsl, I'm not sure where that puts the actual mount point for each boot.
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