You could post pics to make it easier, but from your descripion...

Lose the lamp and just use the heat mat. Close off the top of the tank with foil/tape on top of the screen. You said it's a wood viv, but also said tank, so I'm a bit confused. Also, what sort of hydrometer are you using to measure the humidity? If it's a dial, it's probably giving false readings and your humidity could be high or low, no matter what it says. If it's a digital, then you're probably getting decent readings.

The lamps are probably the worst heat source for high humidity enclosures, they simply suck the moisture out. It's good to see you did a bunch of research before getting your bp, and I'm sure with a little tweaking, you'll have everything spot-on in no time at all.

Congrats on your bp!