Since little Finn is only barely 3 inches I feel like it will be forever before he will be ready for his big boy enclosure(assuming he is a boy).
how fast do they grow? Will he be ready for a 75 gallon by 4 mnths old or later?
He is currently in a ten which I know is small but my 20 gal broke.
Will he be able to go straight into such a big tank or should I figure out something as an intermediate cage?
I do have a 40 gal, my childrens python probably wouldnt mind living in a tub for a few months till the beardie was ready for the 75.
10 gallons really are too small even for a baby, they can't get the proper heat gradient in the tank. A baby will do just fine in a large tank. Just because they're little doesn't mean they need a little tank.
Go ahead and use the big tank a suggested and partition it if he has a hard time adjusting. They can put on 1/2-1" (or maybe more) per week when little.