OK, for those who are interested and tolerant enough to bear my antics here is what I finally settled for regarding amplification of the PC organ music, including Garritan:

I retained only the powered 100Watt sub woofer and discarded all the rest. To this woofer I connected two 12" speakers from a gutted Hammond M-100. The "bass" one I mounted on top of the rotary vane of the gutted case of an old Gulbransen 1100 which houses the entire assembly (the speaker on that one has gone bye-di-bye - some careless cleaner ripped the one cone wire off so it will be dismantled and the huge magnet used for attracting metal things...). The other Hammond speaker serves as a treble and this combination produces a very satisfying result. Deep bass and ample mid range and treble. The entire set-up is now a lot less cluttered and lighter - and I found a good use for those Hammond speakers...

Maybe I will stop nattering about this now...

Nico