Welcome, Westy!
In a previous life I was based in MSP and lived out at Tonka Bay. I still use MSP as a tech stop to central Europe from the West Coast; I fly for a living and have come to depend on reliability. On the boat, that means the priciples of KISS.
I have a 1970 E32 with an Atomic 4. Don't let the chorus of diesel disbelievers sway you, it is a great setup used with the cautions associated with any machinery (including diesels) that contains fuels. I always cringe when I see propane mishandled, or pressurized alcohol stoves treated lightly, yet these same people will extol the virtures of diesel over gas. OK, off of the soapbox.
I get hull speed (between 6 and 7.2 knots depending on sea state and wind) with my A4 at 1900 RPM. I will burn slightly over 1 gallon an hour at that rate, so slightly over that it is tough to see. I have an 18 gallon tank, and a very accurate guage on my rebuilt panel. I have most of the mods to the A4 (oil heater/cooler, crankcase vent, new carb, oil filter mod), and have found it to be very reliable. As I remember, it is a 12x5 2 bladed sailor prop (RH of course). I have been tempted to try the 3 bladed CDI prop, mainly because it would be quieter.
Welcome to the board, and Good Luck with your boat!
Michael Krebs.