nice install, cool that you used the 90 degree adapter. when i installed mine it would have a small dimple in the hose but not something big of a crimp that would get me worried.
as for the can size, i think its good as is. going smaller will require SM to make a custom size, instead i made it easier for him and used a can he already mass produces with a change in hose size.
it might seem big but i think it fits perfect, just flush in the little splace and still allows the hood to be closed np. the can size itself is the same as the rr occ while the height is just a bit taller.
for the installation i didn't want to hassel SM to include the hoses and clamps. the can and mounting kit are all that is needed for installation. simple things as hose and clamps can be easily bought at local hardware store so i didn't bother asking him.
the instruction however there is a youtube diy found here
only rr provides a instruction while all other cans mckinney, etc don't have one so that isn't much of a big deal.
as for the drain, it wasn't intended to be drained while still mounted. to drain you would have to remove the can and drain and reinstall just like the rr occ. most if not all occ require you to uninstall just the can to drain not unless they have a tube leading down somwhere like the bumper to drain which is a more complicated install and not many occ have this. with the drain explained, the size of the can is good as it has higher volume for collection and will require less drain although any can will take awhile to fill up especially on our n54 so imo the size, placement, and fitment is perfect.
the can mount and mounting position is perfect imo the nipple location i can see your point adjusting it a few degrees but at 45 it is still a good placement.
haha and don't worry about the clips that broke mine are even worse