The way it's been going at DHS it's really more about how much space is available past the turnstiles to hold the pre-dawn crowds before the park opens. It's a process dictated by square footage in the entry area, not the total of daily or annual attendance.
Once you've scanned into the park and they've turned on the App for the day you can join a Boarding Group, and from recent memory and a glance at Google Earth it would seem that DHS and Disneyland both have roughly the same amount of square footage in their Town Square and Main Street/Hollywood Blvd. "opening act" entrance areas.
You're on vacation! Smile! This is fun! Get a Boarding Group Ahora!
That tells me that the rate at which Boarding Groups book out won't be much faster at Disneyland than it already is at DHS; roughly 60 to 90 minutes after the App allows folks inside the park to grab one. The vastly higher annual attendance at Disneyland won't have much impact on that early morning process I don't think.
That said, please feel free to correct any of those basic stats I'm using here. Particularly the grand total of about 15,000 Boarding Group reservations available per day at Disneyland's 8am to Midnight operation.