I thought you meant the depth, sorry. No, they feel a little bit tighter in there in terms of circumference.
I got crosseyed at the alignments of that "table"...that 1mm is a lot larger than it looks (ie I can actually it's a bit more cramped around the earlobes, although not really pressing against them), but in your case since you don't like the earlobes touching the earpads then 1mm less is just making that worse.
That said, how are they "touching"? Because the thing with the HD600 and similar, oval-earcup headphones is that they don't have much front to rear length to begin with, and there's a difference between just plain touching and outright pressing against. If your ears aren't getting mashed it's just a matter of getting used to them.
Alternately you can just get rid of the HD600 and get the HE400S or HE350. These come with round earcups that have more real estate front to rear.
Well, ears are literally on either at the top of my ear if I keep 600s bit low or on the earlobe if I keep 600s bit high. I can try to see if I can center them a bit while physically tuck my ears in when I get on my pc tomorrow.
The regular HM5 velours do seem to have 9 more mm of clearance though from stock - I am just not sure if they will fit on 600s.. You have angled HM5, which seem to fit but regular are bit more circular. I will ask on reddit too.
I find my ears being free when I use my beyerdynamic DT880 stock earpads. I wish I can get something similar in comfort.