H1B stamping in Canada - less than 6 months visa validity

I am in H1B visa and max out date is 26-Dec-2014. My perm was applied on 12/27/2013 in EB3. And I am awaiting for labor approval.
Considering my case was not applied 365 days before my H1B expiry date and if my case go for audit I need to go out of country for couple of days to capture 365 days.
At present I don't have valid visa in my passport. And I am planning to go Canada also I applied for Visitor Visa.
Do I need 6 months visa validity for H1B visa stamping in Canada? Can I book the H1B stamping appointment sometime in second week of July? My visa validity is till 12/26/2014(max out). Because I heard from some folks we need 6 months visa validity for stamping. Can anyone faced this situation?