They're knit with Schachenmayr Rheuma Thermal yarn, which is an ultra-soft, laceweight 100% wool yarn I got in another swap last year. The Veyla pattern calls for fingering weight though, so I used the Rheuma Thermal held double on 3mm dpns for a pretty tight fabric.
I made the size S of the mitts exactly according to the pattern, no problems there, the pattern is guaranteed Ysolda quality, easy to follow and without any question marks.
The buttons I had for forever, I think I bought them on a craft fair in Ireland back in 2007 or so! I sewed them on using one strand of the yarn.
My spoilee liked the mitts - how about you?