I used that many ranged bros mostly to allow for easier focus fire and to take out as many Goblins as quickly as I could. I put them in heavier armor for protection against enemy archers and to make it less likely that they’d get poisoned (which would mean they’d lose vision and be unable to perform their role). Since the Goblins have no flanking units in this scenario to target my archers, they’re otherwise pretty safe and can move freely. I feel that crossbows perform better than bows in this scenario because of their accuracy bonus.
For my melee line I used spears and swords only because of their superior accuracy against the nimble Goblins, and all the Kite Shields available for their superior protection against arrows. Again I equipped all the guys with heavy armor because Goblins have a hard time destroying it. I actually could have done a better job there with the selection of helmets.
I had my melee guys basically charge around the Goblin line at the top and bottom while being spaced out a bit so that the Shaman had a hard time rooting more than one guy at a time. He still rooted like 5 the very first turn, but this only delayed me a round or two. Once my guys made it halfway, I released 4 of the 5 wardogs to charge into the center and keep the Goblins occupied and unable to focus down on my melee troops as they approached from two sides. All the while, the crossbowmen kept firing into the Goblin frontline – even if they missed, there was a chance to hit the Goblin Ambushers in the second row before they eventually moved further back. As the Goblin frontline collapsed I tried to move on as fast as I could to pin down or at least get the Goblin Ambushers on the move and unable to fire on my men while the crossbowmen took care of the remaining Skirmishers. That is also where I deployed the last of the wardogs, to keep a Goblin Ambusher occupied for a turn until I could catch up. The Goblin Overseer succumbed to focused crossbow fire, while the Shaman and the remaining Goblin Ambusher eventually retreated from battle.