Dan, welcome to O'day land! I'm a fellow Nockamixon sailer, and I just got a 192 last year. If you haven't joined the Nockamixon Sail Club, consider it. We have a decent sized O'day fleet, and lots of fun cruising activities. We also have some open races including a poker run, and fun water canon wars.
http://nockamixonsailclub.org/join_us Sorry for the shameless plug, but I'm also the O'day fleet captain this year...

Oh, and unless you have a Flying Scott or a Thistle, it's probably better to join as a cruising member, not a racing member...
As for the roller furling and reefing, your best bet would probably be a Shaeffer SnapFurl with a 135% genoa. This would give you good light wind performance, and the sail could be reefed with the furler if the wind gets up. Ideally, you'd consider a sail cut for roller reefing. It will be a bit flatter, so as to maintain better shape when reefed. If it has a foam luff in the sail, the foam will help take up some of the camber as you reef, providing better shape. You can also consider having reinforcements sewn into the foot and leech of the sail at about 100-110%, and maybe again smaller at storm size. Think like the reinforcements in your main at the reef points. For a cruising boat on bigger water, I think the reinforcements might be a good idea, but for Nockamixon and mostly fair weather, I think the reinforcements might be overkill. You will also want to have some Sunbrella strips sewn on the leech and foot, so that when you roll up the sail, the Sunbrella will be exposed to the sun, and not your nice sail.
You could also consider a CDI furler. There are many folks at the lake that have a CDI, but Judy Blumhorst at
www.judybsails.com recommends the SnapFurl, and runs it on her own Potter 19. Judy and I talked about it pretty extensively once. She is a very knowledgable sail dealer, who comes highly recommended, and she's well familiar with our sized trailer sailers.
So, that's a pretty expensive option, what with getting the SnapFurl and a sail made to your spec. But there is a less expensive option that I plan to use this season: you could run a hank on jib with a downhaul line. What you could do is take some 1/2" exterior PVC electrical conduit (the grey stuff) and cut a 2" piece. Cut a slot lengthwise on it, and round over the corners, so you can slip it over the forestay. Drill a hole in each end, and run a 3/16" line through the hole, up the PVC, and knot it through the other hole. Now, hank the jib on to the forestay, and clip your PVC between the top hank, and the next one down. You may want to clip a hank in the middle of the sail over both the line and the forestay. Now, run the 3/16" line to a single block, probably on the U bolt where the Shaeffer drum used to attach, and then back down along the lifeline stanchions. You could run it back as far as the cockpit, along the back of the cabin where the furling line used to cleat. I've been thinking about this, and I might rig it so that it comes back to the mast. Now, when you cast off the halyard, you can pull on your downhaul line, and pull the head of the jib right down to the deck. Cleat off the halyard and the downhaul, pull the sheet tight, and you've got your jib down quickly and easily, and it won't blow off the deck, or try to sail back up the forestay. It's certainly secure enough for you to motor in to your slip. I'm thinking of leading the downhaul to the mast, rather than the cockpit, because I will already be in the companionway uncleating the halyard at the mast, I would not then want to have to move back to the side of the cabin to work the downhaul. Of course, if you led your halyards aft, by all means keep the downhaul at the cockpit.
Benefits of a downhaul include lower cost for the jib, and a better setting jib. Also, the jib would be lighter without Sunbrella strips, so would set better in our breathy summer airs. Admittedly, a roller furler makes life easier at the dock, and makes getting ready to go out that much easier, but a hank on jib can still be stored on the forestay if you get a deck bag for it.
I think in specific answer to your other questions, you would get the Snapfurl CF500 and cut the foil to length
http://www.furling.com/snapfurl.html
If you get the sail for the furler, work with your sailmaker so that they understand that you're using a furling system like the Snapfurl, and what other features you want. A good sailmaker should discuss your typical sailing conditions, etc. to get you a sail cut the way you need. Foils aren't sewn into the jib, rather they have a track in the foil that the luff slides up.
If you chose not to go with a furler, and wanted to just do a hank on, again you could talk to a specific sailmaker, or you could order one on line. Sailcare.com is a manufacturer of a lot of sails that get re-badged, and their prices are probably fair. Brad Linthicum of Linthicum Sails is over in NJ.
http://www.linthicumsailmakers.com/ A friend of mine had Brad make sails for his ComPac 19. I had sails made for my Harpoon by Schurr Sails in Pensacola, and they worked with me well through some issues. It is nice to have a sailmaker close by to work out issues, but that's tough for us, other than Linthicum. And, of course, there are a multitude of lofts down in Annapolis, which isn't too far away.
But, honestly, getting a decent cruising sail cut for the boat will be fine up at Nock, and there isn't that much of a Portsmouth fleet, except for Craig's Santana, an F1 catamaran, and that Corsair trimaran that's just so fast during the ULDB race (Up the Lake, Down, and Back race)
See you out there!
Brian