[markhill]

there are big debates over substrate,I have used both calci-sand and playsand with no problems, some people use floor lino or tiles,others use reptile carpet. Temps dropping at night can be sorted by a heatmat stuck to the back wall of the viv or by using red/blue bulbs.
Size should be ok if the dragons on its own, i prefer to use 4x2x2 foot but yours should be ok.

 

[markhill]

i dont personally believe the red/blue bulb theory from experiance with my royal, but thought i'd share info.