I have filled one usps priority mail bubble mailer to test and be ready. I packed each variety in a paper bag first (remember, they are dirty). But I ended up having to use 5 paper bags because I couldn't remember which 2 I had dug that were the same. As I quickly counted, there will be closer to 100 bulbs in the mailer, or more, because some are fairly small, and each back had *at least* 12 bulbs, and I think only one of the 5 had a count as low as 12.
Holding 2 for sure and those will be stuffed full as one already is, but am going to make an offer to give to the people at the post office next time I go (they were too busy today when I went). I may also ask the Postmaster if he cares if I set bags on one of the tables as "free daffodil bulbs". That way I can get rid of them and be done with them. So if anymore interest, you may want to confirm soon.