Probably the best thing that you can do at this stage is to go out and cast some 4-5 wt. cane rods in the 7'-8' range. It's not as easy to do that as it is to cast graphite; simply based on the fact that: 1. cane rods are not as popular and, hence, are not carried by all fly shops, and 2. demo "accidents", given the price of most cane rods, is a disincentive for most shop owners.
But, if you're in an area where there are some good fly shops, then chances are they'll have a cane rod or two that you can cast; particularly if you look like a genuine buyer.
Another way to go; one that I used before I purchased my first cane rod, was to go to the big Fly Fishing shows, talk to the makers there and cast some of their rods (they almost always bring demo rods with them/and some good deals). That way you can get some side-by-side comparisons which, I think, is always the best way to go. I would also bet; although I don't know this for a fact, that there is an annual bamboo builders convention/show. If there is, it would probably be worth the cost of the ticket/lodging to attend it. That would be a great opportunity to compare cane rods.
Another poster has already mentioned Glenn Brackett of Sweetgrass Rods; formerly head of the bamboo shop at Winston. He's a wealth of information and although he'd like to sell you a Sweetgrass Rod, I'm sure, he's easy to talk to and he'll give you a good perspective on all bamboo rods.
My 5 wt. cane rod is an 8'0" Dickerson 14 taper (8014). Very easy to cast, great feel and plenty of backbone to handle larger trout. No advertisement here, but Ben Turpin built it for me. I've since gone back to him for two more cane rods.
Have fun! You're going to enjoy the trip that you're on a lot; from start to finish (if there is such a thing as "finish" when you're talking about cane rods)!