ye

dang yo

EE should work so long as you have a mod on a ring or ammy that has (adds X-X elemental damage, other than fire, to attacks). This way a non-fire element applies EE prior to the fire explosion.

In terms of damage my opinion is that Kaom's Heart seems more optimal overall due to a good amount of Flat life and up to 40% fire damage, as Carcass only provides 12% increased AoE damage. However if your build lacks overall defensive stats and you wish to pursue the loss then go Carcass. Added AoE and some AoE damage is still nice. Single target may be lacking regardless either way but ultimately you will want to stack as many arrows as possible on top of said target to maximize dps.

I optimized your tree a bit further. We will not need projectile damage as this does not help us at all, we aim for fire, ele and AoE primarily, per skill gem description. One option is to take the ele res nodes near the South start point at Scion, or nab the life regen nodes to the West.

Here is the tree I made, this MAY not be the best out there but it nabs a lot of fire and ele damage nodes along with saving a few along the far left of the tree.

http://tinyurl.com/znh2xkj

Please feel free to message me here or in game.
-KurosMalkil

https://www.pathofexile.com/forum/view-thread/1461017/page/95

This thread can probably answer a lot of your questions

edit: to the post above: projectile damage does affect EA's damage even though it's not in the skill description. Mark has stated it does (somewhere on these forums..) and that's also why a lot of EA'ers use slower projectiles for the MORE projectile damage.

Also, to the OP - Elemental Overload is worth the 1 or 2 point investment (depending on your pathing)

"

edit: to the post above: projectile damage does affect EA's damage even though it's not in the skill description. Mark has stated it does (somewhere on these forums..) and that's also why a lot of EA'ers use slower projectiles for the MORE projectile damage.

Very interesting. Had no idea just considering the skill description. Nice info! In that case def the 'MORE' modifier would be a wise choice.