No doubt that Dallas is a huge MFer. I don't think that the issue will Dallas being tight enough...I believe his serious problem has always existed in the lack of midsection control while posing.
He has a pretty prominent midsection to start with...probably from the vast amounts of "food" he has to eat...and I've noticed (in all the stage appearances I've witnessed) that he doesn't control his breathing well and, therefore, isn't able to keep his stomach sucked-in or contracted throughout the pose.
His glute-ham tie-in is really great and striated already (without a tan), which tells me that he's fairly close to being dialed-in in the lower half, which is predominantly the last half to become stage ready. Makes me wonder if he'll be able to get his midsection under control for the Arnold.
You can use all the diaretics and drugs you want to drop fat and water, but if your GI track itself is big (distended midsection), you can't really get around that. I'm sure he will look respectable and have a good showing on his own, but next to the other pros, he won't shine. I don't see a high placing this year...things can change.
Shit ton of potential...