Though I do not have a DigiQ, I do have a Stoker, and I use the 10 cfm fan with my 22.5" WSM. It works great. No need for the for the larger fan.
Thank the Lard BBQ Competition Cooking Team
22.5 WSM w/ WiFi Stoker | 22.5" OTS | Assassin28 | Traeger Lil Tex Elite | GMG Daniel Boone