I thought I should mention that I have used that Afghans for Afghans pattern almost exclusively for the children. But, I also come out with very different size mittens, depending on the yarn and needles. I just went to take some pics of some to show you all, but my batteries are dead and my step-son has my charger, so it will have to be later.
For instance, there are two sizes in the pattern. I have had that second size come out large enough for a large women's hand, and I went right by the pattern, yet another pair with a different brand of ww yarn fits my 6 y/0 gd. It's just that ww yarn has it's differences and I think even for those of us who knit everyday, our gauge can be different, depending on our moods, lol, and of course our gauges are going to differ from each others, as well.
I guess I'm just trying to say that I've made many pairs with ww yarn without
putting any other yarn with it and others it seemed too thin and I had to add in baby or sport yarn. It's just a matter of trying it out yourself, with whatever yarn/needles you have and going from there on the gauge. Maybe make by the pattern for the first pair, then you'll know what changes you'll have to make.
Think of all the warm little hands this year from all of us working on this!