^ Thanks, that sounds similar to the salesman's explanation and makes sense. I think he was very knowledgeable and wasn't trying to screw me in anyway, I just wanted a second opinion. His thinking was basically that you can't undo the heat molding, so if they stretch a little and I don't need them to, I'm S.O.L.
My old boot is a Nordica and I honestly couldn't tell you much else about it, other than that I never had it heat molded either. I'm no gear head but I skied enough (one or two trips a year) that it was still worth it to me to have my own boots, and I didn't know anything was wrong with it because other than a few rentals I had never skied with any other boots. At first the pain was excruciating to the point that they were unusable, but I figured out that I had them buckled too tightly and though they were still very uncomfortable and it was painful to walk in the evenings after wearing them, they were at least usable. The bulk of my pain was on the outer-sides and along the bottom of the arch. I have a pretty regular foot and have never had any issues with any other footwear I've ever owned.
One thing that did appeal to me about the xpro was the wide toe room you referenced. I went in with the intentions of just asking my Nordica boot that had been causing me so much pain over the years was too small and/or if there was anything I could do about it. He measured my foot and told me that the boot was indeed the right length, but I wanted to try on some others and I decided I liked the xpro enough to go ahead and buy it. I didn't want to have miserable foot pain skiing 6 of 7 days next week.
I wear a size 12 shoe and he fitted me for a 28.5 boot. Even though I wear a size 12 shoe, I probably show as an 11.5 on the slider, which would explain the 28.5 over the 29 based on some online charts I see?
I'm an intermediate to advanced skier, but because I live on the East Coast I just don't ski enough to notice subtle nuances in the boot or its performance. Also, because I've never had a "comfortable" boot, it's hard for me to say whether this new boot needs any tinkering or not. By the standard of my old boot it's comfortable, but maybe it's a 7 and I could be getting a 10 if I knew what a 10 felt like?