To deal with either of those decks you must run white. StP kills oath creatures. Meadling Mage stops doomsday/oath rite off the bat. This is just my opinion

In another thread about fish vs oath i suggested using the bridge. It costs 3 mana but i think it can really help you may just have to get 2 moxen in the deck to speed it up. if you have 6 cards in hand then spirit/akroma cant attack. Get down to 4 cards the other 2 cant attack. I think it is a good idea but some ppl dont.

Putting the white in the deck throws off the whole tempo of the deck. Any bounce can effectively take care of a white/black creature in and G/U deck. So why run the mage. My suggestion is take out the hatchlings and put in 2 waterfront bouncers and 2 guilded drakes. Then get 1-2 chain of vapors/seal of removal/echoing truth/any good bounce and you have them covered. Also misdirection helps against them because in a counterspell war it is basically  another FoW. This is just my opinion though and nobody likes my opinion.

In your area, do they allow proxies in the type 1 tourneys? Most of them do allow 5 just because many people are on a budget or aent willing to dump 3-4000 dollars into a deck. If you find a proxy tourney it can make the deck much better because you need some power stuff

Two things to mention
1)What about ensnaring bridge. 5 cards in your hand and guess what, they cant attck
2)How can meekstone possibly help. Unless you run a way to tap their creatures it doesnt help because i am PRETTY sure both dont tap when that attack.

So what are we gonna do to deal with oath. Are we acctally so scared of it we are going to maindeck some of the anti oath cards or is this all going into the sb. In my opinion Gilded Drake MB is good in almost any machup. At the worst you will end up with a welder or a juggernaut. The sigal would work ok but if it isnt on a Grim lavamancer it doesnt do anything because they DTWA(dont tap when attacking). Also we can run bounce mb because bounce is never a bad thing to have anyways and sense they are G/U they have no way of casting Akroma/SOTN when it is in hand so the brainstorm it to the top of their deck where a rootwater theif can hit it if we try that md/sb. I think it is a very bad idea to take out cloud of faries as mentioned earlier because they are a 1/1 drop that lets you play another 2 casting creature that turn. It also allows you to go fariy fairy standstill. We can consider taking out the spiketail because against oath everything is so cheap it is prettey easy to have that 1 extra mana and they will ofter drop oath before we ever see a turn and unless we drop a mox we cant play the hatchling turn 1 anyways. What would a list look like with trying to get this new tech in?

EDIT: What about ensnaring Bridge. We usually dont have to many cards in hand and DEFINATELY not 6 in hand almost ever unless you dont run cloud of faries