A 40 gallon breeder isn't really big enough for an adult dragon but is fine for a juvenile. That aside, for the basking light I recommend a ceramic fixture/socket, especially with halogen bulbs which can melt plastic fixtures after awhile. Also most plastic fixtures are only rated for 75 watts or less.
Get yourself a digital thermometer with probe and/or a tempgun to make it easier to measure surface temperatures.
It isn't easy to give a good starting point for the wattage of the basking bulb as there are many variables which will affect how well your tank heats up. A screen top will allow more heat to escape than a solid top and vents on the side. The room temperature the cage is in can also affect temperatures. Glass tanks are poor insulators even without screen tops so you are most likely going to need a 75W or more to get the basking temps of 100-120F and ambient temps in the 90'sF.
Under tank heaters are completely unneeded with bearded dragons. They can tolerate night time drops as low as 65F on a regular basis so unless your house drops below that, there isn't any need for supplementary heating.
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PHLdyPayne