Well I only tried the "full" flaps once, which was slightly over 50%,
but mostly I only used the first position(lowest,"On" setting) on my
three position flap switch (off-low-Hi) its not labeled that way just
trying to show what I mean... But even at the 50% it should be no
problem, Just test it 3 mistakes hi:-) and be realdy for the plane to
climb... When I did mix in the elev. I just tried to remember how
much "push" I had to give to stop the climb.. And in a hit and miss
fashion I adjusted the % on the elev.. Maybe someone else will
chime in with percentages.. That's just the way I set mine...

If this is a new plane... Trim the plane out before adding flaperons
otherwise it may not only climb but bank also.... along with any
other thing an un-trimmed plane will do...