I'm right there with you Alan. At my last Games (Bakersfield) I did a double spin for both light and heavyweight for distance, the first time I have ever tried that in competition.

I did great in heavyweight, I had a 22' throw which is close to a PR for me, and with practice I think I will be pushing closer to 30 with the 56# weight.

On the 28 now... I had a best throw of only 36'. That's almost ten feet off my normal throw, and I just couldn't do any better. Part of it had to do with pulling a muscle in the heavyweight throws but part of it was just not getting the form down.
Yet, when I was warming up earlier I was tossing the 28# 45 feet or so consistently.

As you said, practice, practice, practice....