I'll suggest that you use or build a vertical lens support from a hunter's "Shooting stick" or angled bi-leg tool, with 'a "Y" shaped cradle, or a good monopod, with a cradle, which will support the larger lenses, without needing a threaded port on the lens to mechanically attach the lens to.
To use these you just need place the camera on the tripod and, with the lens supported by hand, with the leg of the stick loosened, while you locate the shooter's stick at the appropriate 'midway' point for maximum support in that position, with the support firm to both ground and lens in position.
All that is awkward here is, instead of the single supporting of the lens and camera, is learning to quickly position place, adjust and lock the lens and it's separate support, from the tripod, , quickly and firmly.
You can buy quality shooting sticks at Bass Pro, Cabela's, Walmarts and hunting shops, just be sure the cradles are wide enough for your lens, or make your own wide spaced horse shoe shaped cradle out of wood, plywood, even layers of dense plywood, well glued, all with a #20 ¼ nut or larger size when needed.
Custom made cradles, or hard to find and expensive, locking sleds or otherwise are fine for those that'll not mind the expense, but those of us that need to look elsewhere for solutions for our photo needs, can find or make do with kit outside the "normal" manufactured and "approved" odds and ends to get the best out of our photography, which is the only concern for shooters, not collectors.
IMO.