2-3 bombers based on guild size. Composition/Balance > DPS. Claiming we had more (aside from the very rare woe when we did have 4) is more of a compliment than anything.
So, how about a token system, then. Add a token to each treasure box with a drop rate between 4 and 6%. Consider the final droprate of the item (assume they will be VIP and they will be using HE Gum, always). So 4% will give you ~18% in the end, and 6% will give you ~27% in the end. So you'd receive between 4 and 6 Tokens on average for a 100 Eco Castle.
24 treasure boxes @ 100 eco (or is it 23?)
1 Token Tier:
5 EDPs (random, perhaps)
15 Acid Bottles or Bottle Grenades
5 Yggdrasil Berry
10 Yggdrasil Seed
40~50 HP Potions (A Mastela fruit with 0z sell value)
30~40 SP Potions (A Blue Potion with 0z sell value)
30~40 Healing Potions (A Royal Jelly with 0z sell value)
20 Speed Potions
5 Token Tier:
Speed Potion Box (75) [Contains 20 speed potions in a 1 weight box]
HP Potion Box (200) [Contains 200 HP Potions]
SP Potion Box (150) [Contains 150 SP Potions]
Healing Potion Box (150) [Contains 150 Healing Potions]
Cost Balance vs Weight: A 1 weight box has advantages, so the amount you get out of it should be lower. 20-40% lower.
10 Token Tier
Acid Bottle Box (125)
Bottle Grenade Box (125)
Poison Bottle Box (40)
Enriched Oridecon (5)
Enriched Elunium (5)
And just for fun, you could make higher tiers with Kawaii hats.
25 Token Tier
Crown of Deceit
50 Token Tier
Red Wing Hat 
Edited by Jaffer, 02 October 2013 - 05:38 AM.