What Sam said.....and then take that bucket, or something about the same height as your seat, sit inside it and tape cardboard along the top of the windows - reducing your sight line to the proposed chop amount....I spent hours in and out of mine, negotiating between how much chop and how much could I stand to drive it chopped.....
At least in my car, I had the room to move the seats around, tip them back slightly, etc etc..you won't have that luxury...you are pretty well stuck with a very small cab. It also depends on how tall you are....
Either way, think long and hard before you cut. I'm not slaggin you, just don't want to see you go wrong...