I would not recommend using mercury vapor bulbs in that cage at all, not enough height, Mercury vapor bulbs should be at least 18" above the basking site.
Wattage of bulbs should not exceed the max. recommended wattage on the socket they are screwed into (ceramic fixtures are usually good to at least 125 watts or more. Should be written on the side of the fixture in inside the dome.
For your setup, I would suggest buying under cabinet florescent tubes, and screwing them directly into the ceiling of the cage itself (may have to predrill to get through the plastic...and depending on how thick, a nut or something may be needed to keep the screw from being pulled out...
For the basking spot, I am tempted to suggest just cutting out the wire in a slightly smaller circle than the width of the dome you are using.
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PHLdyPayne