You've already received some great guidance with regard to your question(s). While I cannot speak for the J, I can tell you I love my Sabre 34. My traveler and main sheet are on the coach roof and while sailing with a crew of two it is absolutely no problem. If the Admiral is below and I want to make a change it is easily accomplished using the autopilot. My S34 has a fixed keel (5'6") but a friends Sabre 36 is a centerboard, suprisingly he seldom drops the board. We also sail the Chesapeake and while I must be mindful of shoals and sandbars he pretty much ignores them.
Probably the best advice you've received was to "try on" the boats. Sit in them, consider what is comfortable and consider additional equipment that comes with the purchase.
Consider your purpose as well. If you're all about getting there as quickly as possible then go for the speed, but if like me you think that when you're sailing you're already there...go for comfort and tankage.
Can't imagine a good reason for having two heads, unless you've got a bunch of messy kids that are untrainable.