You want to keep all 20 babies? I suggest you sell as many as you can. All males will have to be in separate cages even if you don't put females in with them. Males will fight if housed together.
So that means, if you run on averages, about 10 separate cages for each male by the time they are 6 months old, maybe 8 months old if you want to push it.
It is unlikely you have a large enough cage or space to house a cage big enough to house roughly 10 females together when they are 6 months old or older (where they should be apart from males). Unless you want to turn a bedroom into a dragon cage. (10'x12' floor space), and hope all the girls get along...not feasible either.
Thus it is likely you will need at minimal, 13 cages, not counting your original pair's cage or cages. At worse, you will need 20 cages, plus your original dragon's cage(s)
as each cage for individual dragons should be 4'x2' of floor space and if you house 3 females together, in a cage of at least 5'x3' of floor space...you will need stackable cages definitely...and that is just when they all reach 6 months of age. Till they reach the age you need to separate them out and have adult cages built or bought, you still have to pay the cost of feeding 20 ravenous babies.
For the first 4 months you can expect feeding them 2-4 times a day, lets say each dragon eats 50 crickets each over the day...you are looking at a lot of crickets. So thats 1000 crickets a day just for babies...over 4 months... say 120 days and you are looking at 120 000 crickets. If you get them for $10/1000 (with shipping taxes etc. and to make it easier to figure out) you can be spending $1200 over that 4 month period on crickets alone. So roughly $300 a month and this doesn't count vitamins, calcium, greens etc.
-----
PHLdyPayne