I use a somewhat different idea behind setting up the elevator/flap ratios. On initial flights I set the flaps for absolute minimum movement (zero in fact) and do the first trimming flights using only elevator. In these flights I just check for wings level upright and inverted, enough tip weight etc before going into loops and squares. I use these to set elevator travel to get the feel I want combined with sharpness of square corners. Elevator movement usually comes out at +-17 degrees or thereabouts.

Once that's set I concentrate on looking for any trace of stalls in hard turns and they always show up in the last corner of the triangle and hourglass. This means more lift is needed so then I'll start setting the flaps to barely move. Each flight I'll increase flap movement until there's no trace of a stall in the tightest of turns then leave them. My flaps move about +-5 degrees but the model has a very light wing loading.

The point about using the least possible flap movement is that flaps add drag and this drag comes at the worst possible moment, just when you want to keep all the speed possible during a hard turn.