Help with sexing Hornworm moths!

[Mutablekitty]

I'm trying to start a little hornworm farm for myself. My moths have just come out of their 'chrysalis' or pupa form. ( Im new to all of these terms so forgive me if I say the wrong word). Now they are adult moths and I'm having difficulty determining the genders. One has 4 dots on its underside while another only has 3 dots. I can't really check by the wings since they are folded up and honestly i'm not too sure what I'm looking for.

 

[TripleTegus]

I know nothing about breeding insects but I would say your best bet is to just keep all the adults together and let nature take control