I haven't tried 28g on stainless but I can see where it would take forever to heat up due to the heat loss. I have used 28g with other wicks in the AGA-T. I seem to burn up enough
juice at 1.6 - 1.8 ohms so I can't say as though I see going any lower myself. If your into the really low resistance, I've heard the Vamo will fire anything using stacked 18350's. I can't see why stacking would make a difference in limits but supposedly it does.