Green card category

[barracudan]

Hi - I am in the US on an L1A. I was in my managerial role in Canada for 8.5 months before moving to the US. My company is now beginning to start my green card application. I am not sure which category but they were talking about the PERM process. My country of birth is India and I have Canadian citizenship. I believe the EB1C category would be the best path for me in terms of processing time but I needed to have been in my managerial role for 1 year to be eligible. Any advice on what I can do to apply in a category with the lowest processing time? Can I do a temporary assignment in Canada for 3.5 months to complete the 1 year requirement (I have been in the US for 8 months now on the L1A) or do I have no other choice other than to apply in one of the other categories that require a PERM certification?