Just wondering for a general idea
It depends on the type of milkweed you have. Tropical does not require stratification. If you do a search on "milkweed" on Prairie Moon's site (see link below) and click on "details" under the photo of each type of mw, it will tell you the germination code. I think most types they list have a code of C30 which means cold stratify 30 days. Hope this helps.
Here is a link that might be useful: Prairie Moon mw search results
you do not need to cold stratify tropical milkweed seeds. This method works like a charm. I would say about 90% of my seeds germinated.
I used method #1
Here is a link that might be useful: Starting Tropical Milkweed Seeds
Here's an article I wrote about the subject.
Here is a link that might be useful: Cold-Stratification
Butterfly Encounters has some nice info/videos on growing milkweeds.
Here is a link that might be useful: Growing Milkweed