John
I used a seamount-mattson bracket. See
www.seamount-mattson.com/twinplat.htm
I probably could have had it fabricated to add more flotation but didn't know. Their work was highly skilled and done on time and a grand less than armstrong.
My motors weigh 416 each or 836 w/o props. I use aluminum.
In a sea, It doesnt roll any more or less, a stern or bow sea it is better because the boat is effectivly longer.
Even if you have a single, buy a dual bracket.
I will email you more pix this weekend.
Brian