Wool sub: different weights/gauge

Hi all

I would like to do another pair of the colourwork mitts by Eunny. The pattern specifies 28-32 stiches per 4 inches, depending on size. I used a merino whose label specified 28 sp4i (and modified one of the patterns to use 30-32). I am making another pair as a gift and want them to wear better.
Ironically, my choices of wool here in New Zealand are very limited (and no we don’t all have a couple of sheep in our back yards :wink: ). I have found a suitable wool - very soft, but entirely acrylic/nylon - that oh happy day comes in black. The label specifies 22 sp4i. The LWS lady seemed skeptical about my substituting it.

I know stranded colourwork already makes denser fabric, but what I got before seemed fine despite being slightly thicker than recommended (can’t compare though, it was my first colourwork). What do you guys think about a 22 sp4i being used here (probably the 30 sp4i size mitt)? Would it be difficult to work on the needles? Much much hotter?

If it helps, here’s the pattern (very cool) - http://www.eunnyjang.com/knit/2006/11/endpaper_mitts.html

Thanks all