I thought 5th & 6th were limited to Unibus
systems.... For that matter,
will 7th even run on a Q-Bus system?
If you have under 256KB of memory, and only I/O devices equivalent
to the corresponding Unibus devices, it should be possible to get
them working. To software, an 11/23 with 256KB of memory is not that
much different than an 11/40 with KT11.
I remember hearing of someone running 6th edition on an 11/23, but I
don't recall who it was, or whether modifications were required.