Based on the photo you posted, I am guessing that your boat has either a shoebox or inward flange type hull-deck join, and if you've got decent access to the hull deck join area, then installing an aluminum rubrail might not be too bad.
I am unfamiliar with these terms and what they mean regarding my hull-deck join, can you please elaborate on what to look for so I can identify what I have?
I agree with what the previous poster said. I like the look of the wood and the functionality of the aluminum. The aluminum would need to be through bolted along it's entire length while you would only need to through bolt the wood at the track. So a key is how much access you have inside for washers and nuts. Depending upon the sharpness of the bends, you might have less trouble with the aluminum but you may need to make a clamping jig or long pipe clamp to pressure them around the curves. The wood might need some coaxing with strategically applied water to help it bend correctly, again using your job-made clamps. Don't forget with either material to use caulk (life-caulk not 5200) to keep water out of edgegrain of wood and help with structural adhesion for either. I'm thinking you might have an easier job with replacing it with wood simply due to the access under the toerail around the length of the boat.
Once you remove the old material, you will get an idea of how the toe rail is presently installed. If installed with wood screw like I imagine, you might need to fill and fair to redrill the holes for best bite for the new screws. While it seems like a big, complicated job, breaking it down into segments will help it go smoother and you should enjoy the result. It's a very pretty boat.
I have really great access to all the bolts of the toe rail (it is thru bolted by the way). None of the bends seem that extreme, but I honestly don't know what would constitute a hard bend.
The w/m alum. toe rail is on sale for just under $700.00 for a 34' section (I'd need two), so it is pricey initially but maintenance free in the long run (I'd imagine). When you say I wouldn't have to thru bolt it all the length of it (a wood rail), how is this possible? It's currently bolted the entire length, and it seems like it would be "loose" where it was not bolted? I'd love to eliminate as many fasteners as possible, but I don't understand how I could achieve this in this application...?
I do plan on bedding with butyl tape instead of a curing product, I plan on bedding everything with butyl actually.
If going with wood, would you recommend shorter sections that would (I think) require less bending, or longer sections that show less seams and endgrain?