I look in some other spoileron/flaperon threads, and the mixing I described seems to be what most guys use. Here's a quote from one guy who uses spoileron/flaperon and elevator mixing...
ORIGINAL: Deerslayer
I have a number of 40 to 60 sized models where I use flaperons, i.e., ailerons which can be deflected up or down. The former should really be termed spoilerons.
Typically, I program them such that significant flap (down ailerons) accompanies up elevator movement, when I have the mixing switch set - flaperons. Additionally, I may have some spoiler (up ailerons) coupled to down elevator movement - spoilerons...
I believe the "proper" spoilers on top of the wing actually kill the lift of the top airfoil, while these "spoilerons" just produce some down force (behind the CG) to counter it... probably why you get some down pitch with the conventional spoilers and some up pitch with spoilerons...