Even I am in same position as you are in.. I renounced the Indian citizenship but have to go for a 10 month project to India. I have a Canadian passport but not sure if I have to apply for OCI from Canada or if I can apply from India.
Guys, please let us know if you have any idea about it.
I wish I could help you out but what I hear that authorities in India are very lax in letting Canadian of Indian origin in. I recently heard my friend and his son were allowed in India for a visit even-though he forgot to apply for his visa ( I don't know how one can forget).
If I was you I would apply for a visa for 10 months as OCI generally take upto 6 months (CGI Vancouver maybe faster in Toronto area) and apply for it in India as you will be there for an extended time.