Have you ever messed with using a rear bag on top of the rear tripod? It essentially converts the position into a modified prone position. It's usually done with a flat tac-table on the back tripod, but can even be done on the crown of a tripod if needed.
It takes just a tiny bit longer to set up, but the use of a rear bag takes away the sensitivity of getting the tripod in exactly the right left/right position when aiming. It's also more stable, IMO.
Maybe worth messing around a bit to see if you can get comfortable/fast with setting it up. Set the rear tripod about 5-6" lower than the front tripod and clip the gun into the front tripod farther out forward on the fore-end to give some distance between the two tripods.