Jay, it's probably already in your head as a guy who has been around, but be careful of what sort of amp you listen to these guitars through. If there's any tonal difference between them that matters to you, it might be covered up by an amp that has too much of its own voice. Ideally, I'd try them through a few rigs. In old-time terms, I'd go for a JC-120, a Fender Twin, and a Boogie. Of course, if you're more into one particular tone and style, go there and be happy. Nothing beats trying a guitar through the gear you'll actually play it through, and you might even bring your current favorite guitar to A-B with the Alembics in real time.
As much as I believe that Alembic is the absolute best, it may be that neither of these is perfect for you. When you're spending new money on an Alembic, it pays to get it right the first time. You may find something missing in the tone that a little discussion will help you get on a new order for a few hundred more. Maybe you wish the neck was thinner/fatter/wider/narrower? A small price to pay for getting it just right. What's a couple hundred when you're heading in the direction of $6-8K to begin with?
If one of these two sings for you, then jump on it. If not, take a look at what it would take to make whatever little tweaks might bring you to the promised land. You're also in an Alembic-rich area. You might take a run up to Alembic to see if they have anything lying about the factory or try to get together with some of the locals to try some more instruments. I know that playing a few other customs really helped me when I decided to take the plunge.
I do have to disagree with Bill on one point. I think an Alembic that fits you perfectly, particularly in neck dimensions, does blow any other Alembic out of the water. If the standard shape and size is what fits you, then you're all set.
Just my opinion...
-bob