The 8103 will do it. I think the 8103 is the base model for mixing it properly in the radio.

As you said the 6102 won't do it. I have a 652 and it will work on a PMix, but only the master servo responds to the trim inputs. The slave just sits there.

PLEASE don't use a reversing Y-harness. They work okay for a trainer or mild sport flying--but if you want any kind of precision--get a JR Matchbox or the Futaba mixer.

Here's why a reversing Y-harness doesn't work perfectly:

All servos rotate different amounts in the opposite directions.

For example:
Any given servo from a cheap GWS nano servo up to the best digitals will ALWAYS rotate more in one direction than the other direction.

For arguments sake--lets say a Hitec 475 Standard BB servo will rotate 60 degrees clockwise and 68 degrees counter-clockwise. This applies to ALL servos. No servo will rotate the same amount in BOTH directions--in the stock configuration. YES, you can use a Matchbox or a radio---as we are discussing here--to make it work the same amount in both directions.

But, I'm talking about using any STOCK servo with a reversing Y-harness.

When you stack the 2 elevator servos in the tail of the fuse- and use a reversing Y-harness--you will get differential throws in the 2 elevators.

The reason is that the LEFT servo rotates 60 degrees when you pull up elevator--and the RIGHT servo is reversed, so it moves 68 degrees on up elevator input.

Opposite thing happens when you put in down elevator input. The RIGHT servo travels 6o degrees down and the LEFT servo moves 68 degrees down.

So, you pull up and the plane corkscrews to the right and when you push down elevator, the plane corkscrews to the left.

Yes, there are ways to whack around with the linkages to get it CLOSE in this situation. But, you'll never get it perfect. There will always be tracking problems with the plane.

The JR Matchbox has come down in price. I think I saw a 2-pack for around $105 recently.

The 8103 has a "trim include" function when you run a Pmix on seperate channels. That will make both servos respond to the trim inputs. It also allows you to set endpoint travel and center on each servo.

"EDITED FOR CLARITY"