Quoting "Q M" Christopher Honkzo6
Excellent, you avoided the mistake of putting the gun towards the centre.
I've been thinking of making one of these, and since I have the tracks to do it, I'm seriously thinking about it.
Advice would be to have a look at some other peoples Hetzers to get a rough idea of how to put in an interior.
there is an interior and it fits a minifig, i'll post pics of the interior today.