Hot Spots and New Shoes

Hey ya'al!

I've increased my mileage significantly this year and I've started getting really bad hot spots. After doing a little research I've learned that many things can contribute to this such as 1. bike fit 2. shoe fit 3. insoles 4. cleat position and 5. riding posture.
That being said, I've recently had my bike professionaly fit, I bought a pair of profeet insoles earlier this spring, I've tried adjusting my cleat position and I've started moving around more while riding. My current shoes are a cheap pair of Diodoras that area a size 43. After trying on other shoes and learning that the shoe should feel a little snug (as opposed to a tennis shoe being comfortable) I realize that I should now be in a size 42. Well, I went out and bought a pair of Specialized BG Comp road shoes, but I had originaly purchased them in a 42.5 (trying on the previous years model the 42.5 seemed to fit pretty good but I wanted the 2010's with the carbon sole). Anyhow, I get the BG Comps with the carbon sole in a 42.5 and find that they are a little big. I took them back to my shop and the guys were gracious enough to order a new pair in in a size 42. When the size 42 shoes came in they were the 2011 model without the carbon sole... I've heard that a stiffer sole can help alleviate hot spots especially on longer rides and carbon is about as stiff a sole as one can find.
My question to you pros out there... is carbon really going to make that much of a difference? I am doing rides of 100+ miles and am averaging around 200+ miles/week.
Thanks for the help