Shape it by hand with a whatever you can find. If you're just making one board a surform may be the cheapest way to go. I use a scrub plane then other planes to smooth it out. Get paulownia if possible or at least western red cedar or redwood. You need a light wood that is faily stable. I guess balsa if you don't mind glassing it. Paulownia, WRC and redwood hold up really well in and out of the ocean even without being sealed!
Boiled linseed oil is good, but raw tung oil is better. Thin either 3 parts turpentine to 1 part oil and apply several coats then go surf.
I ride my alaias all the time from shin slappers to well overhead and always have a blast. Stick to trying to replicate the original ancient alaias cause they work great. Don't get all crazy adding "modern" stuff like concaves or fins it'll just slow it down and make it ride like a dog. The anceint Hawaiians spent a few hundred years refining their designs so why reinvent the wheel?
Need more advice or ideas for your alaia project? Check out Xylemsurfboards.com. Once you build your board let me know if you need any tips to figure out how to ride it, I've been riding/shaping alaias for a while and I'm glad to help.
Have fun shaping your alaia!
P.S. To the guy that said alaias need better waves: If your alaia doesn't work in less than ideal waves, you likely made it wrong. It should work in just about whatever waves the ocean can throw at us. I don't mean to come accross like a jerk, but poorly designed surfboards just don't work right in any surf. Its gotta be right. Right?
can i just use any old saw to cut the blank? and on your site it says you use only tun oil with a citrus solvent. would this be a better way to go than boiled linseed? and in the post you said to to thin them with 3 parts turpentine to 1 part oil so now im confused haha which one should i listen to? sorry to bother you with these probably stupid questions but it definitely looks like you know what you're doing