I am still new at this, but I use a 1/8th, which I believe is 3.2 mm. That's on an AGA-T, so Im not sure if that works for an ihybrid.
It would, and I do believe that is the size that a few of the guys have been using. Tho I do know my AGA-T the wick hole is just a tad smaller than on the iHy.