some questions about two layers of wetsuit for cold diving

[Nitro91]

In the winter here in australia, it can get just below 60F or 16C and my 5/4mm suit might not cut it.
Instead of buying a whole new suit i was thinking of getting a vest to go under or over it so overall thickness is more around 7mm, plus a hood either attached to the vest or separate again.

something like this possibly:
XS Scuba Mens 3/4/6 PyroStretch Hooded Vest with Side Zipper
or
Bare 5mm Sport Men's Step-In Hooded Vest

wondering if any vest will do and how comfortable it is wearing two pieces of suit as opposed to one suit but thicker.

[hellhole]

think the XS scuba hood will be good enough.. i have an scubapro hood. that i wear under my normal 3mm suit..

the mobility is good as its only top half of the body

[Nitro91]

You wear 3mm plus hood for 60f waters?

[faster7581]

that water in the gulf right now is around 60, I wear, a 5mm suit, 3/5 hood/core pull over, and a 5mm shorty, I stay nice and toasty.

[TSandM]

Layering neoprene certainly works, but you have to play with the sizes and order of layering in order to make sure that you continue to get a good, close fit without too much water entering through the neck.