You should ask someone from that Jurisdiction, @funloving might help you.
In Vancouver jurisdiction one can submit both the applications together ,i.e. SC and OCI. Regarding appointment, @vvarma is correct. For SC you don't need an appointment but for OCI you for sure need an appointment. Without appointment they don't take OCIs. Keep on look out for appointment on BLS either Vancouver or Surrey.There is no option for SC. Its either, Passport, Visa or OCI. SC falls under Passport.
I would select OCI, since technically they will have to accept your Surrender since one does not need to have an appointment for SC. However, OCI compulsorily needs an appointment at both Vancouver and Surrey.
So OCI.
Wish you luck!