Also helpful is to work your way up to full flap deflection incrementally. You didn't say what plane this was, but let's say for example we're talking about a Super Cub. The scale SC had a max flap of 40 degrees, which is a lot. So if I were setting up a Super Cub's flaps, I'd start with 10 degrees and see how that worked. Chances are the plane will balloon a little but I shouldn't lose it. So then I'll program some elevator mix to compensate for the ballooning, starting with maybe 3% and adjusting from there. Next I go to 20 degrees with the understanding that I'll get more elevator compensation because the mix is based on a percentage. I'll adjust the elevator comp if I need to, then move to 30 and then the max of 40 degrees. It's really helpful to have a two position flap switch so you can test two different settings at the same time.