First of all, I personally would never play mono-blue without a full complement of Moxen, because you really want first-turn Mana Leak. I think you will find the deck much too slow without them, and if you expect a ton of Fish, it's true even moreso because their deck is the definition of tempo, and yours is the antithesis. So I would recommend finding another deck for this meta, but if you insist, then I shall do my best to help you.
1) If people truly aren't sporting any power, there's no reason to run 4 Chalice. The reason to run 4 is to maximize your chances of a first turn Chalice for 0 after dropping your Moxen. If you don't have Moxen, and no one else does, then try going down to 3. You won't be able to drop a Chalice for 1 until turn 4, and that's about when you'll want to draw one.
2) Running Tinker -> Colossus in a deck without Moxen is not so hot, and you aren't going to want to sacrifice your Chalices or Kegs for this combo, so don't run it.
3) Brainstorm is pretty bad in mono-blue. You don't want to be drawing cards you've already seen. Impulse digs one card deeper and gets rid of the chaff. It is your tutor for a counterspell.
4) If you think you are going to run into stupid Aggro then by all means include a couple of Shackles. I would cut a Chalice (as I said above) and a Phid, which is terrible vs. Aggro.
Hope this has helped you a little bit.
