Bshilam,
The old C-DOG site had a thread about ways to reduce pounding in at fast speeds in short chop. I am thinking those NE lakes probably have a lot of chop.
4 cycle engines were heavier then (that was years ago), but many thought using a heavy, all chain anchor rode, and keeping a light transom would reduce hull pounding at speed. Of course, too much bow weight can be dangerous if it leads to bow steering as Dr. Bob has explained.
I really think you ought to buy from a dealer who will listen to you, explain why he recommends a particular setup (honestly) and finally set the boat up exactly as you wish.
Dealers installing dual engines have to carry larger inventories since they have to give you a brand or two in 40's , 50's and singles in 70,80,90 hp.
Installation of twins requires more work, but most importantly, better educated and more careful installers and that costs more.
After the first few months, you will have little to do with your initial dealer, unless he is the closest, most convenient, and will ing to listen to your concerns over maintenance, accessories, etc.. If he won't listen to you at the start, go somewhere where they will - refardless of doubles or singles.
John