The value of setting up flaperons seems to depend a lot on the plane. I set up elevator-flap mixing on my 4* but never use it because it just makes the plane harder to fly. I also set up elevator-flap mixing on my Nobler and this works well. But the Nobler has true (seperate) flaps and they seem to be designed to work in this way. Engaging the Nobler flaps also helps slow down landings however there is a fine line between setting the throw "enough to slow the plane down" and "too much", which makes the plane prone to ballooning and causes general instability.

Start your mix low- maybe 15% and gradually work your way up. Make sure you program the mix to a switch so that you can fly the plane normally to altitude, then flip the switch to see what happens when you are a few mistakes high.

I also wouldn't try landing with the flaperons acting as "flaps" without some test approaches while flying high first. Be prepared to dial in some flap-to-elevator mix. You will probably see a significant tendency for the nose to pitch up without this mix, which will make the plane very hard to fly. Again, this is something you will have to set by testing the flaperons a few mistakes high, then landing in normal mode, adjusting your mix value as needed, then trying it again.