Glow - if you have to hold 1/2 down to keep it inverted then it is of course nose heavy. Take the CG back to as far as you like it. Mine is also nose heavy with a Saito 72, I got 2 oz in the tail and its still a little nose heavy. I have been flying it too long like that and tomorrow it will have another 1/2 to 1 oz on its tail! Yeah ... a dog to land too!