move back into production. TPTB will likely have to write Spencer out for 2-4 months. I've online that Networks are 7-8 days for 55-60 pages (one 1 hour episode 42 mins + ads).
Streaming shows (Netflix, HBO Max, etc) take longer, but I've never heard of a show taking more than two weeks to film an episode, and usually these scripts are a bit longer, ranging from 60-70 pages.
Also, a lot of streaming shows do crossboarding, so there's really no "per episode" time frame. It's where they shoot all scenes from a certain number of episode in one location, then move on to the next, and next, and so on. That way, they could end up shooting 2 episodes in a month for example, but it's not actually one per two weeks.
Both shows could always try to accommodate his schedule so he could do both simultaneously but that would be difficult I imagine, but it has been done. Ryan Seacrest has flown coast to coast for years for American Idol and his radio show. One is shot in Cali and the other in NY. But of course, it's a lot easier to to do a radio show that wraps in a few hours.
I guess we will see as I believe it will be announced how long he'll be away from GH. There are several viable options the writers have, but as often is the case--we viewers come up with stuff way better than their plots. But I'll give it a whirl on plausible temp exits for Spencer/NAC:
A. Nikolas returns secretly and kidnaps Ace. Spencer decides to go after his father and bring his little brother home.
B. Nikolas returns and announces that Victor left him the same dossier on Esme and he plans to use it to secure full custody. Esme doesn't want to go to jail, so she agrees to give Nikolas full custody. Spencer freaks out, takes Ace and goes on the run to keep Ace out of Nikolas' clutches. He goes to Trina and tells her that he has taken $100,000 and wants her to go with him. Trina considers it but then says no and tries to talk Spencer out of his plan as he will be breaking the law. Spencer doesn't listen and flees.
C. Spencer is Sonny's nephew. They are close. Pikeman has confirmed he's after both Anna and Sonny. Maybe Spencer gets injured someone in a hit meant for Sonny. Curtis was already shot, so maybe a car bomb or Spencer and Sonny are talking in the street and someone tries to run Sonny over, Spencer pushes him out of the way and is hit and goes into a coma.
They will definitely have to get their creative juices flowing to explain his absence from the canvas.