Hi Scott,

If you just want to use the 2600 styles with Tyros voices all you need do is set up a midi registration on the SD card so that it does not receive any right hand channel information. You can then silence the left-hand voice on the 2600 which will leave the style being played by your left hand with whatever voice you have set up on the Tyros.
The Technics keyboards allow more flexibility in separating left-hand voices from styles than the Yamaha boards. With Technics you can set up a bank of registrations with a different left-hand voice for each one without the style changing each time and without having to use annoying "Freeze" buttons. For example if you have a bank of 8 big band registrations and you want some of them to have a brass left hand and some to have saxes or a piano, with Technics you can but with Tyros you can't: Or, if you can I aint found the way to do it.
As I said earlier the most important tool in running these keyboards together, in my opinion, is to have a readily accessible switch in the midi lead so that you can operate them independently as required.
Take care.. Trevor