CAL (Crochet-A-Long) Leader Beate will hold weekly sessions for CAL participants, including either a weekday (Wed 1-3p) or weekend (Sun 1-3p) option. Meet ups begin June 2 (Sundays) or June 5 (Wednesdays), 1-3p.
Mark Roseboom (that's his lovely photo!) recommends a heavy worsted or light bulky; his yarn was 185 yards/100g.
Pattern is written for 11 colors, but you can vary yarn weight and colors. Yarnivore recommends at leas 6 colors (1 main, 5 contrast).
Yardage/grams recommended for 32"x42" afghan:
Main Color: 425g (about 4-5 100g balls)
Contrast colors: about 50g each of 5-10 colors.
Designer recommends an H hook for heavy worsted, which makes a denser fabric. Yarnivore recommends either an I/5.5mm or J/6.0mm if you want something with a little more drape or lightness.