I'll try to make appropriate notes about various personal equipment choices versus requirements as I go along. There are A LOT of different ways to do things, and often one will not be any better than another. Preferences and comfort levels have as much to do with an installation as anything else.

If you have a transmitter that permits slaving one elevator servo with another channel, permitting the use of dual servos to drive a given surface, it eliminates extra or redundant equipment. If you do not have a transmitter that permits this, such as a 6XA or XAs for example, there are a few other ways to accomplish the same thing. One is the use of Hitec servos and their programmer. That's about the only way you could accurately and effectively use a Wye harness to drive a servo pair.

The next way would be to use a Matchbox, Smartfly equalizer, or the product made by Futaba whose name I can't remember that does about the same as the other two.

Another method, which I do not recommend, is to use a simple Wye harness and reverse the way one elevator servo is mounted in the fuselage. This is a terrible way to do this, and rarely matches the other elevator servo.

Servo choices are something that has a lot of leeway. Wild Hare is very good at determining what their planes require in servo torque. As long as the owner meets those requirements the planes always fly well. The level of performance is something that's always up to the buyer regardless of the manufacturer. One can go much higher in performance levels, but that will always be at a higher price. As previously noted, I like to size my servos based upon the plane to be flown today, against what plane I might want to install the gear in a little later. I do the same for batteries since they can quickly add up the dollars when buying more batteries. Might that plane be smaller, having less of a speed or torque requirement, or perhaps larger? For me it's usually larger so I size accordingly.