One thing that I would make sure you do is to spend the money to get real fish arrows with a safety slide. These are much safer to use than modifiying a regular hunting arrow.
If you can not afford the nice AMS reel I would look inot getting a kit so that you can mount a regular fishing reel onto your bow, if you have a decent quality high capacity reel lying around.
If you do not already have a reel I would suggest looking around on ebay to find an AMS reel. They are really really nice and you can get in about 10 shots to 1 over the plastic drum type reels. You can pick up just the reel for around 70 bucks on ebay.
Also make sure that you use a really heavy line.(Mine is 130 lb nylon cord)