Nah, 32mm with 3mm walls (so 6mm in total). Might have been overkill. The second one is getting 32mm with 2mm walls.
The strut plate is 5mm HDF again, just cut the bigger version and sprayed it black. 
Taking them off takes a few minutes, so you can still do that. I slid the core to the very left after undoing those screws and then just pulled the strut plate out to the right after unscrewing everything.