I'm sorry Roberto, I didn't catch your first post about the FatBoys.
I would suggest NOT having a FatBoy in the neck pickup. My experience, like the others here, found it was too boomy, just too much, but I had to find out for myself. I was going for overkill, and I succeeded. Luckily, I was able to swap it with the bridge pickup of my MK, and so now both of my basses have the FatBoy at the bridge and a standard AXY at the neck. I like soloing the bridge pickup, and the FatBoy works very well in that position. The regular AXY gives much more definition on the neck pickup, and gives all the bottom end one really needs or could ever ask for. Ok, except for a real Series...
Moral of the story? The good folks' experience shared here is correct, and I should have heeded their wise insights. It worked out great for me since I had another bass to swap the pickup with and the cable was long enough to make the swap.
I look forward to seeing your bass. Alan, ajdover, recently put in a post about what to consider prior to your order or to at least bring up when working out the details with Alembic, and he gave great insight with regard to string gauge and other areas that will ensure you get the bass you want. The only thing I would then stress is the neck dimensions. Know the dimensions of what you want, including frets, and be sure to let them know. Mine were pretty easy. Stanley's, 1960 thin Les Paul with 6230, and 1.5 thin jazz bass with 6230 on this custom. I love Stanley's profile, and they carved the necks just how I wanted on the other two. I'll assume since this is a 7 string, that the neck dim's are high on your list.