Race + long run pacing

Hi! I’m training for the NYC marathon and it will be my first marathon. I am also doing 9+1 for 2025 so I am running the Staten Island half on Sunday. I have to run 20 miles on Sunday so I was going to run the half and then run 7 miles after. What do you recommend for pacing? Do I race the half and then go slowly on the 7 after? Or should I use my easy run pace on the half and the 7? Or do I try for marathon pace on the half? Any guidance or suggestions would be helpful. Thanks!