Converting Primer/Varnish Channel to a 2nd White Channel

I am printing 2 white layers beneath 1 CMYK layer on a Mimaki UJF-7151 Plus Flatbed printer. This printer is currently set up as Primer/White/CMYK (6 channels). I wonder if I had replaced the Primer channel with a 2nd white ink channel would I see a significant speed increase? I am using two white layers as this provides optimal density.
You would have to talk to Mimaki about that. Yes it can probably be done as you just flush that line out. They would have to get involved so that the printer/software is recognizing that as a white channel. as far as increasing print speed if your using 2 channels as white you might not need a 2 pass white but I would bet you would.