Frankthetank,
There are some bigger boats (45' - 55') that'll accomodate up to 7 anglers, but it'll cost about the same as 2 smaller boats. The big boats will be in the $1,400 - 1,500 (per day) price range. But it's still 7 guys on ONE boat. Plus, that doesn't leave much room on the boat if you decide to take along a chica or two! And don't forget the 15-20 percent customary gratuity for the crew.
IMHO, you should get 2 boats. You can find them in the $700 - 800 per day price range, and each person will have more time on the rod (no pun intended).
Best bet is doing a search on the web for charter boats. You'll find a ton of them out of Jaco and Quepos, with Quepos probably being your best bet. If you can book them ahead of time, it's probably a good idea, but it's not crucial. If you don't get a boat ahead of time, you should still be able to book one (or two) through your hotel.
Most of the boats will run offshore, and troll for billfish. Either that, or they'll stay inshore and slow-troll live baits for roosterfish and cubera snapper. I've never chartered a "bottom fishing" boat in CR. But I'm sure they're available. But the charter company would have to know this ahead of time, so they can catch the live bait before you get there, the night before or the morning of your charter.
Also, keep in mind that the larger concentration of fish are moving North this time of year. The biggest numbers are being caught on the Pacific side.....from the Carillo / Samara area, all the way up to the North, between Flamingo / Playa del Coco areas.
Bamboo rod and tin can ??? I don't know about that. The fishing in CR is good, and the waters are fertile. But you still need a captain that knows what he's doing, and where he needs to go to find the fish. Some days, the fish are chewing, and other days it's mediocre. The fishing can turn on and off like a light switch. You might catch a dozen fish today, and then get skunked tomorrow in the same area. If you're a sport-fisherman, then you already know this. Nothing is guaranteed.
And don't worry about a boat with 2 fighting chairs. I've never fished in CR on a boat with 2 fighting chairs. Most of the fish that you catch will be fought 'stand-up' with a harness, on 30 # class tackle or less. The only time we sit in the fighting chair is when we hook into a fish over 300 lbs. Other than that, it can all be done "stand-up".
Have a great time.
Mucho Gusto
