I'm assuming I'm going to have to drill out all these screws that hold it together, any tips?

These ones too

The whole windshield

I just removed the windshield frame from my 47 truck. I just took a 1/4-20 nut, positioned it over the head of the screw, filled the nut with weld and all of them came out. I was able to put a wrench on the nut and remove them. I guess the heat doesn't hurt either.
Good luck!!

what i did on my [really] rusty cowl vent screws,which were smaller than those holding your windsheild frame together, was to heat up the head to almost turning a very dull red, then place a birthday candle on the screw for about 10 seconds or so. the wax melted down around the head into the threads, and the screws came right out with very little effort. just make sure you watch your fingers as the candles get short kinda fast. also, make sure the screwdriver you use is the biggest, best fitting one you have that fits the slot so you don't cam out the slot, causing you to revert to "plan b".

I got all but 2 out using a combination of PB Blaster, heat and a impact driver

If the 2 remaining are near others you got out, clean the open holes and screws and reinstall tight. This will help relieve pressure on the stuck ones...