Evaporust i swear by, on my Edsel i took the entire front bumper assembly off and soaked it in evaporust. it took it right back to bare metal like it was fresh in the assembly plant, and that was a North dakota and Canada roads car, lots of rust and snowy roads to traverse. That was soaking it for 24 hours, though. IF you need to, get creative. sand down an area best you can, then pour some evaporust out into a small tub and paint it on with a brush, be prepared to keep painting over an area for 5 or 10 solid minutes, keeping it wet so it activates properly. Another option might be, get a gardening tray, put some sort of rubber edging like you have on car windows, or sealent on the edges, flip it upside down, then weight it down. then, cut a hole in the tray, pour the evaporust on, and voila. You've seen my comments, you know i'm wanting this to succeed, i'd never steer you wrong :)

I'd definitely go with 10 Guage for the main power to the lightbars, they pull about 5 amps a bulb/rotator. Also I'd put main power to a relay and use a switch to power the bars. That way the relay takes the load and not the switch.

2:21 you can see the "cut out" in the frame where the futura windows would go, I learned this from fifthrider when they started cutting away some of the floor in their old superior (so they could put jump seats in it), that the frame was either prepped at caddy or the coach builder for both a hearse and an ambulance - even though fifth's 59 was also a straight hearse