Static margin is 4.5 %
Next WE I will make more test in order to move a little the CG. I also have to add airspeed. I can see some small pitch oscillations in the log, 5 to 10° of magnitude, but I do not see them while flying. I think a big problem is the quality of flaps servo, you will see that while flying fbwa or Auto the PWM range used is very very low, less than the gear play.
I use Corona fast HV servo connected to a 6V BEC
They are very very fast but have some amount of play, not bad for a low cost metal gear servo but maybe too much for these large flaps.
I think the wing is able to carry more weight but of course the CG must remain at the same position for all 3 axis.