@stuart sounded like a sweet little tournament. I always like to read about small localized metals and the way it allows for fairly unusual deck building decisions, compared to the a "typical" list from mtgo or a big tournament. The Problem here is just that while I would like to give my opinion on card choices, Ian just not sure if those choices I question are another result of your local meta.
On another note:
Iam a little scared that a lot of blue decks (Xerox maybe, landstill, especially big blue, ...) might start to play the new dampening sphere, probably in the sideboard, mostly to slow shops and PO down.
Blue decks starting to play easy to cast taxing effects might be a huge problem, since most builds are either geared (after boarding) to fight against opposing countermagic or to fight against opposing taxing effects, but not both. The sphere slows often slows their own game plan down a bit, but leaves the deck functional while we have to find an answer to it since we cannot win with it in play.
It reminds me a bit of matchups against blue countermagic wielding decks with troublesome permanents like Leovold or Kambal. I always hated those matchups, it is very hard to protect against both of these angles and still have a functioning Deck. However, I expect dampening sphere could become a much larger part of sideboards in a variety of decks and be a regular threat we have to handle.
Do you have defense plans on that? Bringing in more hurkyl's recall instead of boarding it out in addition to the typical countermagic answers could be a possibility, but that would probably come at the cost of watering down the storm aspect of the deck more. I usually liked Tinker/Bot against troublesome permanents in blue decks like Leovold, however sphere might be played in the same decks as Dack fayden.