Re: Life vests for the well-endowed
Type II are close to the most uncomfortable life jackets you can buy. They are the cheap ones sold by west marine to meet the USCG carriage requirement of one for everyone aboard. Don't even think about them for general wear, they are terrible, and manufacturers have no intention of making them better since they do what they are supposed to.... Live in a bag somewhere to show off when the Coast Guard show up.
Type I is like II but actually more comfortable. Though they are full jackets intended for off shore use. Again, don't think about them for general wear, they are hot, heavy, and not really designed to be comfortable.
For always on, the only realistic option is an inflatable. I appreciate the concern about sharp objects, but the covers, and bladders on the USCG approved list are very durable. I have one that is now about 8 years old, and still passed certification this year with no maintenance done.
Take a look for type V inflatables with type II performance (type II must roll you over on your back if you are unconscious). Ideally spend the extra to get a true type II inflatable that doesn't have to be worn to meet carriage requirements, since that way you have an extra life jacket on board.
As for manufacturer... I like the Mustang or Musto brands, but they are both heavy off shore types. For more moderate sailing, I would just go try as many on as you can. There is a lot of variation between manufacturers, and models.