okay, here goes!
palkia is probably best as a 0-1-of: (it isn't so important that you lose when its prized that 10% of the time) any problem starting with it solved by float stoning to it (which u wanna do anyway for the kick start max elixir). If you are going to use dce, then using palkia setup is a little pointless as elixirs will keep enough running through to attack over and over till at least your 3rd attacker if your opponent is streaming ko's, (in which case the deck isn't working).
a 3rd trubbish is an idea to play around with so you can drop 2 at once more easily (preventing your opponent taking out garb before it sets up)
Jolteon seems to be here just for a non-existent threat??? (no energy) It's probably not worth the energy split over other cards, baring in mind you already need 2 specific energy (W+DCE) to attack for the most part.
Manaphy feels like a target that doesn't work with the deck as much as float stone(I do recognise fright night yveltal as a threat to not using manaphy but escape rope exists and its not like your putting shays down)
dive ball probably doesn't deserve 3 copies: just because you arn't using shaymin doesn't mean ultra ball isn't good. e.g. dump lysandre or delinquent or glaceonEX (matchup where you don't need 3 of them) when you can only N to get a new hand. e.g.2. sycamore,vs seek, ultra ball, flare grunt, is your hand: you're going to use sycamore and discard everything anyway, but ultra ball can search whatever you like rather than just a water type. In short, ultra ball was good before shay came out.
Stadium choices here are difficult, but I'd say raikou/electrode is the hardest relevant matchup for this deck but I havn't tested extensively so I can't say whether rough seas counts or not for a large amount in other matchups.
Having mentioned raikou/electrode, this is the matchup that convinced me how good hammers are in this deck. (try out hammers to combo with flare grunt)
+1 trainers' mail and +1 N is probably a good plan for shaymin substitutes.
super rod isn't neccessarily a neccessity.
splash energy is kind of wierd for a deck playing 4 max elixirs and super rod. If you really need 6 regice something is being done wrong: if its for decks like raikou/electrode type decks, hammers tend to work. Any future decks like the passimian deck; parallel city can be effective aswell as a 3rd fury belt in the matchup.
Phew, that's long (over 400 words...), keep playing around with it!