Thanks a lot Valveman!
You mentioned: with 6” casing I can put a 4” shroud on the pump, which I think is very important for the longevity of the pump/motor. So, if I do go with the 6 inch well, it appears I need a shroud for my pump. The well digger did not mention anything about this. Where do you get this item? And how is it installed?
I just make them from a short piece of 4", 100#, sewer pipe. Cut three pie shape wedges out of the top. Use a 4.5" hose clamp around the wedges that are left to tighten it to the pump. Then tape over any cracks with good electrical tape. Here is a video of installing a shroud, it is just on a larger pump.
http://www.youtube.com/watch?v=sVBpCVqX7Jk