ohboi_jc
Here is the link to the cage size calculator. You put in the length and width of your cage, and it tells you how many birds should live in the cage:
http://www.finchinfo.com/housing/cage_s ... ulator.php
When you put in the current size of your cage-22"x22", it will tell you your cage is suitable for 1-2 birds. If you double the length, as it would be if you hook a second cage together with your first, 44"x22", it will tell you that you can put 3-4 birds in that cage.
You already have 4 birds in your single cage. That's crowded. When you double your cage, it will be appropriate for the birds you have already. Not more. You now have males and females, so the possibility of breeding and increasing numbers is already present.
You cannot add more birds when you double the cage size. You are already full. It would not be fair to, nor healthy for, the birds you already have, to add more, especially of a different species. Do you really want to knowingly mistreat your beautiful birds?
Slow down, take a step back, start reading and learning and
listening, please, before you make a mistake for which those little birds will suffer. There is so much excitement with first birds, the thrill of new acquisitions, but you need to reign it in for the sake of the little lives you will be playing with.