Anyone attach an REL sub to Cary amp?

I like the way the REL subs connect into a system, with the signal being transmitted to the subwoofer via the speaker terminals on the amplifier rather than an output on the pre-amp. However, on most Cary tube amps there are only one pair of binding posts, or as in the case with my amp, a neutral and both an 8 and 4 ohm tap (I use the 4s). This would require having both the speaker cables and the sub cable connected to the same set of binding posts. They are multi-way binding posts that could easily accommodate the second set of wires for a sub, but I'm a little uneasy about doing it. Has anyone ever tried this with a Cary, or any other amp with a single set of posts for that matter?
I'd feel safe in assuming that many people do that without issue, as long as the contact integrity of the main speaker connections is not compromised. (How the sub wires are physically connected is way less critical, since the sub draws almost no current from the power amp).

As a point of info, though, I would see no problem with connecting the + wire from the sub to the 8 ohm tap while connecting the + wire from the main speaker to the 4 ohm tap, although of course that would still leave you with two wires connected to the ground terminal. Doing that would result in the sub receiving a slightly higher input voltage (about 3 db higher), which would be compensated for with its level control.

-- Al
I use spades from my REL cable on the same 5 way posts that carry the banana plugs for the main speaker cables so they stay out of each other's way. The REL puts a very high impedance load (100,000 ohms?) on the amp output so it shouldn't burdon it in any meaningful way, and it works very well. Not sure if any other sub uses this method, but that's one of the things that attracted me to the REL sub.
I have a pair of Cary CAD 300SE Signatures and do just like Wolf_garcia - spades for the REL and bananas for the main speaker cables.