the 500AH comes with one long plate which will fit your scope. If you want to mount other stuff like your camera on the fluid head too w/o having to unscrew the plate from the scope, you can get more plates as needed.
my personal go-to head for a full size scope is the Manfrotto 500AH fluid head. It does most things right, the only little issue is that it uses proprietary plates (but replacements from either Manfrotto or chinese cloners are readily available).
With a fluid head, you can set the friction...
that guy called OpenandShutterCase in the thread below is not per chance your friend?
"I'm interested in your opinion regarding the 80c. Did you get the leveling base? I might get it for my gimbal and birding shoots."
If yes, the...
maybe you can try your friend's setup with your scope and let us know how it worked out? From the specs the Innorel (not Manfrotto) RT80C legs look ok (160cm w/o head is plenty, 22mm lower section diameter is good too, 3 sections would be better than 4), but not all CF tubes are created...