You'd better do it in Canada, just in case you need additional documents and you can't get them right away if you apply for visa in China. 7 r0 @$ ^0 W) g* ^+ Z+ q* ?4 I2 m6 S3 U% q7 S" Q
Submit your application to Detroit through FedEx, my experiences, normally 10 business days.
My experiences: 5-10 business days (Several cases) 2 Z$ g/ l& o. ]$ N0 A) ?, M* X4 \( V: e3 Y. i0 F' W; x: z8 o
right place, right way, right documents