I will be honest and tell you that a 10% T8 will never recreate wild exposure in a viv of that height.
It is vital that reptiles are able to self regulate in an enclosure between a wild type uvindex, heat and light, then into cool and shade.
I explain this in much more detail in the lighting guide section of Arcadia Reptile : Arcadia Products Plc
But if you want an easy to use plug and go system that is very affordable and has the electronics, reflector and the correct lamp included then a 24w slimline T5 fitting will be fine for a viv this long.
You will however need to increase the viv size as they grow!
I'm happy to help further if required
John Courteney-Smith MRSB.
Arcadia Reptile; Head of Science and Innovation
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