HSS 2 volume wiring

[SDK2]

Hi All, i was following this . I use 4-wire ducan pickups. In this configuration in which push-pull slugs will the red wires from the middle and neck pickups go? B2/3 are already taken in this config.
https://ru-clip.net/video/3r-3LMLGl..._kHkvGk3aJnDIqqldv-IcHzlm4v1VDVvAooToI1JQcwQs