We are recent parents of a juvenile Beardy...and just a little paranoid that we are set up correctly!
We have a 48x24x24inch tank with an Arcadia 39w Pro T5 UVB kit mounted on the ceiling.
Although powerful, does the T5 have a reach of 24inches to the floor or is it worth mounting the UVB lower on some sort of plinth to maximise the UVB on ground level?
Our dragon has a raised basking spot under the heat lamp, but the UVB does not extend all the way to the basking area....so when he is directly under the UVB lamp, he is generally on the floor.
They definitely don't need to be in the optimal output range constantly, that's just for basking (they don't always need to bask). Providing a bunch of options is a good idea if you can. Have a platform or branch etc that allows closer access to the UVB, but also have shade areas, and possibly areas that are warm but have little UVB. Creating zones for them to choose from is the best way of going about it, in my opinion. They'll move around and get what they need at a given time, as long as they have good options available.