I suspect asking for fuel economy on your 200 by changing th prop might not get you quite what you want. Generally, a solid hole shot comes from a prop with less pitch than one for best cruise MPG. Because the torque to turn it at a given RPM is a bit less. So there will be more throttling losses. The articles on the Eco prop I have read make me think that differences it makes are trivial. I think anyone who bothers to research and try props will make a decent compromise and get far superior performance to one who uses the first suggestion for their boat. I don't think the Eco is magic based on what I have read. IMO
If the price is no different then certainly try it. Benchmarking it against similar props on the same boat would be useful.
Also lakes and oceans aren't the same. 1 day in 10 I can use a F100 at WOT for any distance at all without getting airborne in buzzards bay (the Altlantic).
A heavier motor is a faster trip to the bottom, though.
Edit: that merc isn't bad at 390 lb for 200 hp, though!
But I can see how a high altitude lake might be different. But if it's that smooth, I wonder about a Seacraft being the right hull for the application?