Mid-sized repower

[Wreckless]

I (my wife actually) bought an 18' Lowe last year, that we use as a duck / bay boat. I bought a WELL used Merc 50 to power it. I knew the merc was tired so I'm looking into a repower. I want a prop. 4 stroke, unless someone has a better idea (etech). It'll have a tiller and be used mostly for hauling around a BUNCH of decoys and a couple to 3 people. Then Crabbing, Clamming, some Salmon on the LC (I also have a sled), maybe out to the whistle at Newport (ON A FLAT DAY!). It weighs about 1000# with battery, fuel, anchor. It has a slight "V" and a tunnel bottom so it rides REAL smooth in chop.

Questions:
Will the high output motor be faster when loaded? Unloaded? Not at all?
Do I even NEED a high thrust motor? (could I just get a higher thrust prop on a regular 60hp?)
Am I overthinking this?
I don't want to go over 60 because of weight. Am I being to cautious? (It's rate to 70-75hp with remote steering)


Of course I'm looking for Max. torque when she's loaded with wet decoys and my fat.......Body. AND speed & efficiency when we are running around unloaded. I know, I know........

Thanks in advance for any tips, hints, ideas.

Wreckless

P.S. The good news is I'm in no hurry, but the Merc is TIRED and it's a buyers market

Thanks again!