I don't understand the "should've started" part. Taylor changes that all the time.
A caveat here should be that the only BTO sheet that should be trusted to be accurate is the one your dealer has while you're putting together your BTO. I would never put complete faith in one someone on a forum sent me.
If you look at www.tobiasmusic.com
The BTO sheet prices are good from jan 1st-march 31st
Then April first a new price sheet comes out and woods may come back on the list or removed.
That is what I mean.
All I'm saying is that Taylor makes changes at the drop of a hat.
A few years ago, Cocobolo was the big thing. You couldn't swing a dead cat without hitting someone who was building a BTO with Cocobolo. Well, Cocobolo was still on the BTO sheet when Taylor Guitars wrapped up all the Cocobolo they had and locked it away because of Lacey Act concerns. They didn't come out with a new BTO sheet, they just said "Nope, can't get it" when someone wanted Cocobolo.
Some other things to bear in mind is that certain things can't (or won't) be used with others; certain purflings won't be used with certain bindings, etc. There's no way to know that by looking at the BTO sheet.
The best place to get a BTO sheet is from your dealer, who gets it from his Rep.