Dont forget though, COMPLETELY blacked out windows aren't legal for racing. Not sure if thats one of your major concerns, im sure appearance is higher on your list, but i thought i'd mention it.
Try windex, or even plastic safe motor sprays work sometimes. Don't use normal thinners though, i've found it degrades the lexan and makes it more prone to cracking.
Hope you sort it out, i've found the same thing at times with that smoke, but once you get the hang of ridiculously light coats it works well.
Have fun!
Robbie