As to soldering the wires together and then to another wire (like a "Y"), I'd use some 10 or 8 gauge wire easily available from any car stereo shop. That's actually a good idea if it's done right.
The double wires frustrate the hell out of me,i could never fit both into a 5.5mm plug so end up with them soldered to each other (one shorter than the other)then one to the plug,messy, and seems like the same resistance bottle neck as just one wire in the first place.
With the hi-amp lehner motors i just solder both wires straight to the windings.
As to soldering the wires together and then to another wire (like a "Y"), I'd use some 10 or 8 gauge wire easily available from any car stereo shop. That's actually a good idea if it's done right.
Once a method is worked out, maybe sticky it?
I think im going to try it - I will experiment at the end of the 2 wires - ( if i mess up - im going to cut 1/2 of the wires off anyway ) I will probably use 8ga wire. It has got to look clean and neat. Maybe i will take a couple of pics and sticky if it works out.... Thats definately an idea