Sorry for coming into this discussion late, been busy all week.
I prefer the three-shade, it works just as well and might allow better recolouring later on (camo schemes etc.). That is the main objection to too many shades. What does the reverse shading look like (aft facing turret)? This is another important consideration too.
I wonder if the double-black line at the front base might be better being v. dark grey and black?
I'd love to see the 16in updated too with similar styling.
The double black line in front is actually because there's a slightly raised armor plate there. It's one of the reasons the vertical face armor didn't save as much weight as originally thought when applied to larger turrets. there needed to be a measure of protection where the barbette came out from under the turret.
I took the liberty of also doing the 16" turret in this style, and placed all renovated turrets onto the weapons sheet, so you won't have to.
Also, the face plate of the 6" turrets was angled way too far backwards.