Get used to flying only in 180 degrees in front of you. The turning around you are doing will get you in trouble at any field where more people are flying. Behind you is supposed to be a safe no fly area where people can work in the pits. in the video you said your cg was wrong because it wanted to go down. Weight distribution does not affect the trim that much at the speed you are flying. wing incidence and the rear stab incidence will have more effect on you. Manually retrim the linkage to give you more throw in the proper direction. If you move the wieght to far back the plane becomes very manuverable and unstable and if you move it to far forward it becomes docile until you want to land then it plants the nose in the ground when you slow down to land because the trim becomes less effective the slower you get Same for tail heavy except you get into a stall. the flat bottom wing trainer will rise when you fly faster so trim for a reasonable flying speed and be aware that as you change speed your plane will rise and fall based on speed