[gumby79]

I learned to drive in big 4×4s 98-2010,uhaul box trucks99-2000(probably 20-40,000mi on "truck runs) ,and slantback "up Armor "HMMWVs (aproxamitly 12×12" side windows) 04-06. Theas experiences have taught me to plan were I'm going to need to see and drive to accommodate the visual limitations. Yes backing trailers around corners with only side mirrors.
This is my personal reasons for not even worrying about a back window.
The one on the left was my style of HMMWV
notice how much smaller the side windows are.
Don't get me wrong . I've had to get out and look a few times. But normally back into a parking spot so as to not come out blind.
Think of the lack of a window as parking between 2 moving trucks side mirrors will do the job . With my taper 5' cone is my blind spot.
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If lane changes are your consideration for Windows, then consider convex spot mirrors. This will save weight =+mpg. Save construction cost, time,materials =+$ . Less compromised design =better curves =+mpg. Smoother finish =+mpg ,almost all windows we find have some sort of bump or recess having a negative effect(exception factory glued in wind screens)

--- look at trunk hinges don't remember specific make modle, some have very nice articulated +gas struts lift/hold assist.hinges
Gumby Stay Flexible