I have a heavy gun that has always had a barrel on it with a diameter of 1.75" or 1.85" since day one. That was what I had when I bought it in parts back in '99. No barrel block, but bedded out about 4". It has proven to be competitive through out the years.
I also have two other HGs that have 1.450" barrels, chambered in 300 WSM & 7mm Rem Mag. Both have done well also, more so the 300WSM, as it was shot a lot more. But neither had a barrel block, but bedded out to the 4". They both weigh in around 40 lbs. The first one comes in at 90 lbs. It is for sale, as my doctor who preformed surgery on my back a few years ago said that I should not be lifting as much weight from now on. I will miss shooting it as it has filled the walls with a lot of real fake wood.
Point being, I believe that the heavier diameter does have some benefits, such as absorbing more heat, being more rigid, and maybe less recoil & easier return to battery. The smaller barrels, easier to lift....
Danny