Just a few thoughts:
That full wall slide will add weight to that side. On a 450 it probably won't matter too much but it might on a 350 :@
So you don't get stuck if a problem occurs , do yourself a favor and learn the mechanics of your slide so you can release it to get it back in if it gets jammed in the deployed position. The larger the slide the more people you will need to push, 'if' it can be pushed back in.
Make sure your floorplan will offer you a means to balance the load from side to side.
If you decide on having air bags . Some people add air bags with a dual path system in order to accomplish the load balance.
Some mfg.'s offer bags as standard or optional equipment. ex: Sunseekers come thru with the less expensive single line air bags but Sunseeker LE's do not have any bags. If that's a priority for you make sure the you see the physical bag , don't take a salesmen's word for it.
Be advised getting an rv dealership or truck shop to add aftermarket bags might be a challenge or if any agree to do it be very labor expensive depending where you live. Shops like to order their owns parts and not have you buy them on-line.
My experience with storage bins/compartments.
Some of them are not very stout as far as the mounting of them. The bigger they are the more we carry in them.
Many owners have to reinforce them somehow in order to carry any kind of weight .
My simple fix:
I only carry very lightweight items that I seldom use in my OEM bins and have covered the bins using some leftover flooring strips equally spaced apart to support a load, 3" wide oak flooring crossmembers and a plywood cover. I left about 10" of access room so I can reach under the plywood to reach those seldom used items. An old awning rod acts as a 'hook retriever' extension pole .
I have a solid 1.5" lip around my full width rear bin where I screwed in (attached) the crossmembers (supports) then placed the plywood on top of them. Now I have a solid platform to carry heavier items. Otherwise those flimsy bins will eventually pull down from the edges where they are mounted and who knows what would happen at that point.