It is indeed very cramped, even for a small sized guy like
me.
Unfortunately i haven't come across any interior photos of the
SM1. I suppose you are welcome to come by the next AOH, if you are
in luck they will still be showcasing one of these old
workhorses.
There is a true blue AMX-13 in Labrador park, not sure if the
hatches are welded shut, otherwise can go in and have peek.