I bought my only Peterson, an estate, a few months ago. It's a system 314 with a p-lip and I love it. If I had to pick only one of my pipes to smoke forever I'd pick the Pete. Though, I would probably advise against the p-lip. I hated it at first and looked into a replacement stem, but by the time I'd done my research I started getting used to it, and now I don't mind it at all. Don't really prefer it, just don't really notice a difference anymore. I suppose that it is nice as a change of pace in that it'll give my tongue a little bit of a rest if it needs it. But I don't see a big enough advantage to it to warrant having to get used to it. It's an excellent clencher and the system works flawlessly for me. Never need a pipe cleaner until I'm done and ready to clean it. I think that 317 is made to be exactly what you're looking for if you don't mind a shorter smoke. If you want something a little bigger the 303 or a 314 would be the ticket.
Let us know what you end up settling on - and how it works out. Funny you say you're looking for the perfect pipe because I was doing the same thing, getting obsessed with one design after another until I found and bought the one that I thought would be just right, and it wasn't quite right, and I moved on to something else. But since I got my 314, I haven't been able to find a good reason to buy another pipe. Not that it's stopped me. :lol: