I highly suggest using snipers over shotguns, they offer better odds of you winning vs. breaking even. And since it seems to be a Thorn-fest in there, Red Death wrecks face in it. Another good weapon will be TLW if you've got the upgrades unlocked, with MIDA Multi-Tool being a decent third option. Long range is gong to be your friend here.

Anyway, here's my advice for the different spawn points.

OUTSIDE

My best advice for this is always push left if you're spawning outside, and as soon as you take down an enemy, push up to where their Ghost is (if it's safe to do so). This will prevent them from reviving their teammates. Always assign one player to watch the middle and right side so you're not flanked. Be wary of enemy snipers right around the corner.

When the heavy ammo round comes up, have a Striker or Voidbro make a run for the enemy Heavy ammo through the right side and super the fuck out of them, we bagged that round several times this way.

INSIDE

Frankly, spawning inside kinda blows, we found it challenging to stay together as a team without blocking each other.

My best suggestion is to rush the enemy down your left side (their right), using snipers and Scout rifles for longer range options.

If you're facing a particularly tough team, I suggest using your left-side stair area as a choke point, excellent for Bladebros and Strikers.

Overall, being on the inside area more or less requires a defensive playstyle to consistently win, whereas it'll be far more beneficial for the outside team to play aggressively.

The key tactic is to always, always, always push up to the enemy Ghosts after you kill them to prevent them from being revived. Be wary of Sunbros and Keeper of the Pack exotics, which by the way, you should definitely be using if you can at all.