spruce is it your son that has a connect T230 as well?the room in these vans is great!its like a tardis!! 
i will make sure i use short screws!
Its my son in law and its the L220. It has a payload of 825kgs where yours is 900kg but the body is the same.
Its big enough for him - he has a 500 litre tank in his and he has his running length ways as well to give him space on the sides. He has a set of extendable ladders on one side, his hose reel at the back, a plastic box with clothes and that is all he carries.
The only issue he has is that he has a steel mesh bulkhead and the only way his SLX22 will fit in the side panel is at an angle and the brush head adjusted back. The other option was to put in a pipe holder as you want to do and cut a piece of the mesh out so the pole will extend into the cabin.
But he has worked the way it is for 2 and a half years now and he's happy.