Matt, there's no problem finding PFDs in larger sizes. You have to make some personal choices about what's important to you.
For convenience the automatic inflatables are tops, but they do require some vigilance about inspection and maintenance, and it will cost you a fast $30 to replace the mechanism when it pops--accidentally or otherwise. And you've got to carry a spare, so you still have a working vest after it has popped. ANd if you're going to sail offshore or after dark, it pays to get one with a harness built in, which is going to bump your price to something like $200++
I consider manual inflatables worthless, since a large number of MOB's get sent overboard after or with an impact and are unconcious when they hit the water.
With traditional PFDs, Type1 are so bulky that they are impractical for most recreational sailors. Type2 seem to get ignored, and Type3 are certainly convenient and stylish and affordable--but they don't offer much floatation, they're really intended for "I fell off my skis and the boat is coming right back for me."
You may want to try some on, in the water, to see how much floatation you need. It takes a surprising amount of floatation, located low down on your body, to get your mouth above the water and spray and keep it that way. And a crotch strap to keep the vest "down" and make the most of what floatation it has.
My personal choice? An inflatable PFD with harness, bought before they were USCG approved in the US, because I'd used floatation devices in SCUBA and knew how reliable they could be. And with anything bulkier...I know I'd just never be wearing it on a regular basis. Nothing really works, unless you're going to wear it.
Practical Sailor did a review of them, might be available online. The Uk Crewfit came out tops for them but oddly enough it still is not USCG approved, or popular in the US.