you have a UVA producing light only (besides the basking light?) You should have a bulb that produces both UVA and UVB (a bulb producing UVB will also produce UVA but not the other way around).
The basking area should be designed to give the dragons a choice of areas to go to bask. It is good to have a section of the basking spot hotter (say 115-120F) with areas slightly cooler (95-110F) this way the dragons can move about on the basking area to warmer or cooler basking temps as they need. The cool side of the tank is fine.
As you plan to house two dragons, it is best to have several basking spots with identical or close to identical basking temperature areas. Or a very large and wide basking spot, either wood, brick or rock or a combination of bricks, wood and rock. Each dragon should be able to on individual optimal basking areas, instead of competing for a single one.
Be aware that not all dragons get along and even groups who have been getting along up to now, can and do suddenly become hostile to one another. You will have to watch for such signs of fighting, over domination, etc. If one dragon seems to hide all the time, rarely eats, is always underneath the other dragon (ie stacking), starts loosing weight etc, then you deffinitely will need to house them separately.
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PHLdyPayne