I bought a Paradox out of Canada that had an Excal stabilizer w/ it. it mounted on an 'L' brkt under the rail via the two bolts to the riser.

I've seen 'Ted' w/ an Excal w/ two stick-on Limbsavers on each limb. According to Excal co-owner, Bill T, one each costs you 15-20 fps.

Fwiw.