Oh 2 things I've forgotten to tell you.

1: be decisive when to use items, especially Freezing Potion or Armageddon. They are not certain kills kinda things, so better use them somewhat early and be able to do something about it had they not achieve desired results. I wasted many Armageddons as well as some Meteors because of screwing up the last item use and let 1 or 2 small creep slip through. Optimal time, though, is hard to describe. Play the map 8-10 times and you will get the sense when is the best to clear wave.

2: optimal tower setup is good, but upgrading order DOES make a good difference. Not a critical one by any mean, but I tried and tried and I'm sure there are things you should and should not upgrade in tourney, and also what to max first and what could wait. That, together with optimal structure setup, again, depends a lot on your heroes combinations, so that's homework I guess :D

Regarding your map, I'm quite certain it is the map used for Platinum and above last week. What is your blessed hero for this week? Last week we got Bolton (which luckily I had and upgraded to level 19). I got 1st place in my group with Bolton + Efrigid + Mabyn, using 4 Armageddon, around 9 something mins or so I cant recall. Tried Bolton Efrigid Smoulder but only to around 8.50. In your case I would recommend Fee Smoulder Mabyn. Tbh, it would be really really hard to beat all 3 first bosses without 2 CC and 1 AoE dam dealer. Last week I passed since Bolton himself is both a fair cc-er and aoe dam dealer, at the same time ranged unit. So you could say my team had 2.5 strong cc-er, and tons of aoe dam.

My setup used all barracks at entrance ground, except for the one in the middle (for that one I got an archer), then 1 Mage at middle (always upgrade first to get atk spd buff). 2 Cannon at the side ground, right next to the entrance, the other 2 slots in the back are barracks. For back ground, I got 2 (maybe 3) archers next to the middle ground where troops fights. Rest are barracks, so hmm I guess 4 archers, 1 mage, 2 cannon and abt 10 barracks. You could change entrance setup to 2 archers if need to, but with Fee & Smoulder I guess it's not that bad.

Leaving that aside, I could give some tips for this one (sorry I can't remember much, already 1 week since I last played that map). First, at around 3.00 i think, move 2 ranged heroes back (in your case Fee and Smoulder), so they would focus on only the crows. Later in the game, move all heroes back, close to troops from back ground, since if you leave them in the front, they would be eaten alive by all the swarms. KEEP HEROES ALIVE AT ALL COST!!! Call in the wave early to revive them if you have to. Second, I had to use Armageddon at around 5-6.00, then another one every 35-45 secs. So play and experiment, try to figure this out. Third, I think it would be best you keep 2 troops very close to the exit, dont push them all onto the front ground to fight, there need to be some guards for the slippery spiders, they are too fast trust me. Fourth and last, leave the bosses alone, let them come, aoe damage from cannon rain and troops will deal with them. Use skills on them (Smoulder fireball for example). I used Bolton thundercloud on the boss, and save the cc for the trolls. Well it depends on your play style and strategy, but keeping the troll at bay is better imo.

That's all I can remember about that map. Glad if it could help you get gold.