Sometimes the top can be off the enclosure. I don't use the top on mine and haven't had escapes since the basking spots are too far below the top to allow climbing over it. I also have no other animals in the house that can get in. You can also just keep the light on the mesh top and just raise the basking area to allow closer access.
I would adjust the way you have your thermometers set up. Put at least one of them right on the basking surface rather than stuck to the glass/side of the enclosure. You may find that the basking surface temp (which is what you want to read) is getting warm enough and no further adjustment is needed.
If the basking surface is still reading too low, you can bring your dual fixture back in to play and use a halogen basking bulb there that is dimmable. Connect that to a dimmer and adjust the output to tweak the temperature as needed. You can do this with a ceramic heat emitter as well.