RE: Need trim help.
One thing to remember is do not worry about the suggested CG position once you set it where you like it when it flies. I could not tell you where my IMAC planes are balanced at any longer. I started out at just a tad behind the recommended position but I can tell you I'm way ahead of that by now.
Do not assume the CG is correct until you can get a good calm or semi-clam day.
Also, from this point on and once you have the CG set, the elevator trim you are carrying will also change once you get to changing the engines thrust angles. So for the time being, don't sweat that at this point as well
It's also perfectly normal for a plane to pull to the canopy on a vertical downline. As the plane builds speed coming down, the wing is making lift and since the lift vector is now horizontal versus vertical when level, the plane will want to pull to the canopy, it's an aerodynamic principle. In IMAC trimming, which is what the trimming articles and charts are teaching you, we mix that out using a transmitter that is capable of mixing (most are these days) Elevator trim does have an effect as well. Engine thrust angles will also change this but to a much lesser degree.
Again, please use the article I linked to. It's much cleaner and easier to follow and it's still written by Peter Goldsmith. The original one was written many years ago when you built airplanes from kits and had the decent ability to change what he says in that one, like incidence angles, things like that.
One thing I just noticed in your post is you mention tons of yaw and coupling when inverted and holding elevator, you should make sure your servos are moving EXACTLY the same amount at EXACTLY the same time all the way through their complete travel. IF they are not equal, then all sorts of problems not related to CG can happen and you'll do nothing but chase the settings and never get it trimmed.
Easy to do, take two spring type close pins, glue long straight balsa sticks to them, clip them to the same spot on each elevator half and have them meeting behind the rudder, now SLOWLY move the elevators using the radio and watch the end of the sticks, then should stay exactly in sync all the way through both up and down. MAke sure your elevator are set to prefect neutral before you start. A good way is to place the plane on a decently level surface, turn the plane and radio on and measure from a point on each elevator (make sure it's the same point on both elevators) to the surface. They should be the same.
Why we are checking things, do the same thing with the ailerons. You do not need to be on a level surface for this. Make sure any aileron trim you have in the radio is taken out, IE make it neutral, then make sure the ailerons are aligning the the end of the wing at the root. Now move the ailerons one way and measure, now move them the other way and measure, the through would be equal. If not and if your radio supports it, just use the travel adjust to fix them. This only works of you are using two channels for the ailerons instead of a Y connection