If the response follows the pattern I've observed, B+G will be told that this has never happened before, and the system works perfectly on the test car!
Get B+G to pass your complaint to Suplex directly. I don't doubt that the problem with the canisters is weak springs, I understand that they have experienced problems with stiffer springs fracturing during use.
The bush walking can be solved by reducing the inner sleeve by 4mm.
As to the secondary spring, my opinion is that it is there to keep the slipper joint/knuckle from coming out of the upper arm under full extension.
I wondered about putting them back in.
I hope you get a successful outcome to your problem. If you end up trying the all rear canister set up, I will talk you through my modification, as long as you don't pass it on to Suplex!
Honestly, if I could go back to March, I would go the TF subframe swap route.