Never tried a shirt, they didn't have them back then. It's kinda like cheating. How much would it add to say a 405 bench?
You would need to train with it thoroughly, it's like everything, you becomes good at what you train at. Some guys don't get more than 20-30 lbs from it, and it doesn't matter how much they train with the shirt.
But you could probably with some 3-4 months of training reach a 500 lbs benchpress, depending on how much fat tissue you're willing to put on.
![Cool 8)](http://www.getbig.com/boards/Smileys/classic/cool.gif)
You have short arms, a stocky build. Which indicates you would have no big issues with the shirt.
Most of all, you need to be strong at the lockout, and the top of the ROM, where the shirt helps the least.