On a mech 1.8 dual is probably too high. I do 1.4 or so in a single, or two 1.4
coils for .7 ohms net.
Not sure if the vv4 can push 1.8 dual, but I imagine it could as many manufacture heads are dual from 1.6-2.2 these days (if memory serves, I don't use them, so I don't know! Lol)
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