The aggregrate has Perry slightly holding more than 26% of the total GOP poll, almost ten points in front of Romney. Split the remaining "candidate" numbers fairly between the two, and Perry may be ahead today about 56 to 44%, which is a nice lead.
I don't even know where your Mormon Math get this...
Fairly splitting the remaining vote would indicate where these voters are likely to go when it's down to two guys.
Let's use the Aggragate numbers, since they are all after Perry announced.
RealClearPolitics - Election 2012 - 2012 Republican Presidential Nomination
Bachmann's voters. (8.8) will all go to Perry. So will Palin's voters (10.6) So that puts Perry up by another 19 points. I think we can also safely assume Herman Cain's voters will go to Perry. So give Perry another 4.7 points. so that's 24 points on top of his already impressive 26.3 That brings Perry up to 50.4. I think the kind of people who support Santorum would also go for Perry, so that's another 2.0.
So then we have who can Romney filch from? Well, Guiliani is averaging 7.3, so let's be generous and give Romney those when Rudy opts not to run. I guess he can get Huntsman's whopping 1.2%. Maybe if you are in a generous mood, Gingrich's 4.5 might go to Romney after Newt gets his matching funds checks and goes on a spending spree at Barneys...
So 16.5+7.3+1.2+4.5. = 29.5.
Between the two of them, that's about 79.9% of the vote. So what about that other 20%.
Well, you can deduct Ron Paul's 8%, they won't pick a side until it's all said and done. That's still 12% that hasn't picked a candidate. Assuming 20% of them won't vote for Romney because he's a Mormon, (because 20% won't vote for a Mormon) that leaves about 9% that might side with Romney if he makes a really, really convincing case. So, really, best case scenario, all wind blowing in the right direction, Romney can maybe get 38%. Maybe. I don't think he'll get that much, based on his poor history. I also think everyone who gets out of the race will endorse Perry when they do, because nearly all of them dislike Romney on a personal level.