Alan,
I don't have much experience with the short scale Alembics like the Stanley Clarke but given you are going with a 4 string, I would guess standard tuning (EADG) should be no problem.
As funkyjazz mentions, the balance of the small body, even with the short scale, is an issue with some players (not all though). I've heard a wide strap combats this problem.
Your next issue is where to find the right Alembic for you. Being a lefty player really limits the supply of used Alembics. I look at eBay regularly and I can't remember when I saw a lefty Stanley Clarke. I'm sure they are out there but hard to find. You can always order one new (and you would be able to get everything you might want) but they are very expensive. If this is your first Alembic, I think it's very difficult to know exactly what you'd want in a custom. That's why I went through 3 used Alembics before I ordered my custom.
My suggestion would be to find any used lefty Alembic, try it (either by purchasing or trying in a store), and see if it works for you. If it turns out positive for you, then you can play it until you are able to order one to your desires. If you don't like it, you can probably sell it for right around what you paid for it.
Best Wishes,
Bones