My 50 5-window is stock and if I cut my cab down I would have to stick my head out the driver's door to see! I even have a sun visor I'm hesitant to put on in fear that I won't be able to see very well. I enjoy living in the past-when I was a kid I thought the cab on our 50 was as large as a bus!
Measurements and remeasurements are very important because these mistakes would be very hard to fix. In my experience doing body work I tried to plan the cuts and welds in spots that were easiest to work with and less likely to show. You could contact those like Phat, Ken, MARTINSR, Tony, and many others that have made their trucks something other than it was originally. I admire their talent because when it is done it doesn't look like a butcher job.
But for me I want to preserve part of my old past as long as I can. Ask a lot of questions and have a plan. Good Luck!
