I fly mine at 72 mm cg and that seems just right,dont think it should be more forward.
this plane needs lots of speed,it seems more stable the faster you fly it.
I had a 46 in mine and have pulled it to replace it with a 55 ax.
You say that you have plenty of expo on the elevators,mine are set at 50 % and she is still touchy. I think you should try flying with the cowl on the plane has a very short fuse and with such touchy elevators they could be in the turbulance caused by cowling being removed.You have a very wide front end on a short plane now,i might not be right but i would not fly mine without the cowl.
Also the extra drag is going to kill your airspeed and thats what this plane needs,i am sure mine will be a hoot with the 55 in.
Just the fact that they all take so much runway to get airborn shows the need for airspeed.
You say the plane just dropped out the sky on landing approach this also lends me to think the missing cowl is to blame as they do need a ton of speed to land but yours will bleed speed extra fast and the turbulance created by the large unclean frontal area will disturb the airflow at the high lift area around the wing root.
This plane will also develop lift over the canopy due to the shape but again in your case i think not.
Good luck,dont give up.