Just added a shurflo 4048 this afternoon to my set up what a night and day difference it makes!!
This is my first year with a 4008 and SS3 Controller... Wow!
My advice is to plumb in a small recirc line if possible. Yesterday afternoon I checked on my system and sap flow was drastically slowing down for the day. I opened the recirc line a bit, vac increased greatly, and sap was again flowing heavily for a few extra hours. I probably gained an extra 0.5 gallon/tap after opening the recirc. These Shurflo's like to pump fluid a lot better than air...
Enjoy the 4048!