Re: modifying heel on a neck-thru soloist
That is not a bulky neck joint. A Les Paul is a bulky neck joint.
I'd suggest leaving it alone. You don't want to be weakening that area of the neck joint, and it may well result in loss of sustain and the appearance of dead spots on notes higher up the neck. Besides, the difference between the two joints you have shown is pretty miniscule. It's not like you're chopping out a bolt-on strat heel.
Unless you're absolutely crazy about playing at the top of your guitar's register and have abnormally small hands, I wouldn't worry about it.