I would definitely concur that being overbowed makes it very, very hard to get good form quickly... or maybe ever... and far more of us are overbowed than not. I did it to myself this morning... went out with too heavy limbs on my ILF DAS and blew my form to heck... and I'd been working to get it back.
Also, and some will disagree, but I'd start at 8 yards and not move back till you can put 80% in a 6" circle consistently. Then, move back no more than 3 yards. Continue that process. When you get to 15 yards, you may have to settle for a 9" circle, but I'd bet that in 3 weeks you can be staying at 80% in 9" at 20 yards... especially if you drop down to 45# or less for learning purposes. First comes form... then comes building up the weight... then comes realizing you didn't need that much weight in the first place. That's called wisdom... generally sets in at around 70 years of age...
Dick in SEattle