The other option I can think of, is that you could
change the unit number
on one of your RL02's, either by snapping fingers off the ready
indicator, or (probably a better idea) sticking small plastic rods or
similar into the holes where the fingers go in the ready lamp for the
2nd RL02, and use that.
A little bit of googling or "ask-Tony" :) should help you figure out
exactly how to trick the drive into being another unit number.
From what I remember, and you need to the RL printset
to check (I will
dig mine out if you're serious about wanting to do this), the
RL's
'ready' lampholder has 4 internal switch contacts, which are
opened/closed by the shape of the top and bottom edges of the 2 side pegs
on the lamp cap. In the RL, only 2 of the contacts are used, as a binary
encoding of the unit number.Oh yes, there's a fifth cotnact that detects
there is a cap in place (and disables the drive if not).
I wouldn't mess about with the lamp cpas themsleves, since any
modifications are not easily reversed. What I would to is remove the
front panel from the drive, remocve the switch/indicator PCB from that
and do the changes there.
Now, what I can't remember (as I said, I'll check the prints if you're
serieous), is whether a closed contact is a '1' or a '0'. If it's the
former, then the kludge is easy. Just solder a wire across the
least-significant contact, and your drive 0 becomes drive 1. If it's the
latter, then either cut the trace ot the least significant contact (so it
appears open to the rest of the electronics), or remove the lamp cap, and
solder a jumper across the 'cap present' contact, and across the most
siginificant drive number conact.
Doing it that way has the advantage that it'll be easy to undo the mods
when you want to put the PDP8/a back together.
-tony