Could any of you shed some light on use of flaps while dolphin flying? I.e., in my DG-400, cruising at 70 - 75 knots with -4 degrees flaps, if I fly under a cloud and want to maximize the climb without thermalling, what is the best approach in terms of shifting gears with the flaps? I assume this is dependent on many different factors, but is there a general consensus about whether or not to down-shift to 0 degrees or positive (thermalling settings) flaps when flying straight?