If i were you id save up hair more money and buy the 96" model
Retics will out grown 72 in no time and the 8ft helps ensure more stretching room.
and with cages this size if room is heated to a stead 78-80 flexwatt is all you need. RHP work either way but work best in cool rooms.
This one would be better suited size for an adult but could built it WAY CHEAPER.
T70 (96L x 36D x 24H)