This is what I use for Kai, if it helps at all. Its perfectly okay to get things as you can afford them, since you are pretty good with the 40 gallon size and how you have it set up right now. But Ill show you the stuff that can last your guy all his life, if you dont mind. This bulb for uvb, with this hood:
(Zoomed Reptisun t5 10.0, or Arcadia t5 12%). The t5 made by these companies is consistently reliable and lasts just under a year. With the 40 gallon you have, the t8 you have is fine, but t5 is the uvb of choice for 120 gallon tanks because it will give you the output you need. The zoomed reptisun t5 10.0 and hood are both available at petsmart too, that where I got mine.
Your basking bulb is a good one. As for wattage, its just something you have to play around with until you get your basking spot right, around 100-107 is preferred. Some dragons like it lower, but they need at least 96-98 to digest their food. With temps above low 100s, juvenile or adult dragons get too hot and dont bask long enough. So you are not off by much in the tank size you have. But you might possibly require a little more wattage for a bigger tank. I run a 150 watt in a deep dome in mine (120 gallon) and it just about gets my temps up there. But, like I say, its trial and error. Hope that helps!