Best way to connect Rythmik f12 with Parasound a23+ and Vandersteen 1c's

You would parallel the sub in by running a jumper from each model one if your 1 use spades just stack them at the model 1. IF the model 1 use banana, get a set or two of Pamona banana jacks The preferred way is to parallel back at the amp … you should try to find a Rhythmic manual .

@tomic601 I currently have banana plugs out of amp to banana plug into vandys.  The A23+ has a pretty thick sheath out side of gold plated posts the banana plugs sit into- could i get away with bare wires from the sub into posts on a23+ under banana plugs from vandys?

Yes assuming your amp has five way binding posts, preferably with holes for bare wires. 

@tomic601 I had a buddy with some decent speaker wire so I now have appropriate lengths of 14 awg w/banana plugs out of amp and into vandys; almost the same length of comparable wire out of holes in 5 way binding post (screwed down tight w/no exposed wire) from l/r speaker out's to bare wire eagerly awaiting the sub that goodwill has yet to ship out...

moved some stuff around and I now have a good amount of room behind and left of the left vandersteen that will host the F12..around 4 feet from corner of the room.  I AM READY!  likely my one year old son will want to play with it so i'll have to think of some sort of baby proofing..

will keep posted w/results

Awesome…remember to check out Vandy owners forum , lots of Model 1 owners there…. ;-)