Apparently I'm an idiot or my memory sucks. I thought my 20CV had 2 bronze and 1 nylon and my others had 1 bronze and 1 nylon. It appears they all have 1 bronze only and the 20CV has an additional nylon washer. Sorry for the confusion. I only checked on 20CV and one 420HC Vantage.
I just measured several of mine. All large Vantages. I measured right behind the opening hole (toward the handle) centered on hole vertically. I'll have to check on washers later. You can see pics of the washers from my 20CV version here. Here's what I'm getting for blade thickness. I measured each one twice with calipers rather than converting the numbers. There's obviously room for error on my part.
EDIT: Apparently BF doesn't like tables. Switching to lines.
EDIT2: Apparently BF doesn't treat spaces the same with Courier font. Will try to clean that up later. (Would be nice if BF supported BBCode or HTML tables.)
Steel Thickness (in.) Thickness (mm)
20CV 0.114 2.89
20CV 0.117 2.98
420HC 0.118 3.00
420HC 0.118 3.01
420HC 0.119 3.00
S35VN 0.116 2.94
13C26 0.118 3.00
S30V 0.115 2.93
The 20CV and S35VN, and S30 and slightly thinner stock. I'll check the washers on the S30 and S35 later. Had to feed the family.