I've only tried that mount on a GG Trail Pistol with the bottle cages hanging down from the top tube, haven't tried with a bike on the downtube. It was wide enough that my knees were constantly hitting the bottles. It also looks real silly, but some may not care about that.
I think the best solution is using a mount to stuff two bottles in the triangle. I used Lyne Components for inspiration (because I wouldn't pay this much for just a mount)
https://www.on-lynecomponents.com/collections/the-holy-rail/products/holy-rail-dual-cage-kit and I 3D printed my own bracket. It's about 100g if I remember right, super stiff, and I can design it fit the frame perfectly. Here's a picture mounted on my LCFS911, not too easy to see in that picture but it shows the concept. The mount shifts the forward bottle cage up one bolt hole, so if you mount a cage on the FM936 using just the top hole and it fits, and then if you can hold a bottle between that and the shock, I should be able to make a mount that will fit. I've also got a 1:1 PDF of the mount that you could cut out and see if it fits without modification.
