I'm with Stephen on the bridge block. Over the years I have had 5 Alembics, all different models, 4 with and 1 without.
If at this point I found a nice one without the block, I am thinking I would pass on it. Great choice on the Essence, after my
Series I, that is my favorite electronics package. I, too would consider the 3 position switch at 0-3-6. Good luck with the build.