Sale 1:

Sold for 12 keys + ~1 key in items

No outpost

Seller: https://backpack.tf/profiles/76561198014269804#!/compare/1504915200/1505001600

Buyer: https://backpack.tf/profiles/76561198168676105#!/compare/1504915200/1505001600

X = 13

Sale 2:

Sold for 12 keys

No outpost

Seller: https://backpack.tf/profiles/76561198312583107#!/compare/1502236800/1502323200

Buyer: https://backpack.tf/profiles/76561198278847140#!/compare/1502064000/1502496000

X = 12

Sale 3:

Sold for 12 keys

No outpost

Seller: https://backpack.tf/profiles/76561198358556666#!/compare/1503100800/1503187200

Buyer: https://backpack.tf/profiles/76561198274139380#!/compare/1503100800/1503187200

X = 12

Sale 4:

Sold for 12 keys + 1 ref

Seller: https://backpack.tf/profiles/76561198274139380#!/compare/1503100800/1503187200

Buyer: https://backpack.tf/profiles/76561198213963716#!/compare/1503100800/1503187200

X = 12

Sale 5:

Sold for Kill-a-Watt Crocleather

http://www.tf2outpost.com/trade/29368547 - B/O of 11

Seller: https://backpack.tf/profiles/76561198129088942#!/compare/1505692800/1505779200

Buyer: https://backpack.tf/profiles/76561198234831480#!/compare/1505692800/1506124800

Easily caps.

X = 11 (Capped by B/O)

Sale 6:

Sold for Orbiting Fire Elf Esteem (10.5)

No outpost

Seller: https://backpack.tf/profiles/76561198213963716#!/compare/1503187200/1503273600

Buyer: https://backpack.tf/profiles/76561198268830855#!/compare/1503100800/1503187200

X = 11

Sale 7:

Sold for 8 keys + Strange Compatriat (3)

http://www.tf2outpost.com/trade/29373231 - B/O of 11

Seller: https://backpack.tf/profiles/76561198040898430#!/compare/1505692800/1505779200

Buyer: https://backpack.tf/profiles/76561198051616613#!/compare/1505692800/1505779200

X = 11

Sale 8:

Quicksold for 10 keys + < 0.5 keys in metal

Seller: https://backpack.tf/profiles/76561198268830855#!/compare/1503187200/1503273600

Buyer: https://backpack.tf/profiles/76561198066088040#!/compare/1503187200/1503273600

X = 10

Sale 9:

Bulk for Logo Phantom

Seller: https://backpack.tf/profiles/76561198168676105#!/compare/1505001600/1505088000

Buyer: https://backpack.tf/profiles/76561198080266279#!/compare/1505001600/1505088000

Sale 10:

Sold for Terror-Watt Professional’s Panama

No outpost

Seller: https://backpack.tf/profiles/76561198381136912#!/compare/1500940800/1501027200

Buyer: https://backpack.tf/profiles/76561198216631153#!/compare/1500940800/1501027200

Can be used on the panama.

Sale 11:

Bulk for Heart Rotation

Seller: https://backpack.tf/profiles/76561198199838507#!/compare/1505088000/1505174400

Buyer: https://backpack.tf/profiles/76561198129088942#!/compare/1504915200/1505174400

Sale 12:

Bulk for Frostbite Panama

Seller: https://backpack.tf/profiles/76561198061489334#!/compare/1500940800/1501027200

Buyer: https://backpack.tf/profiles/76561198381136912#!/compare/1500940800/1501027200

Sellers:

14 keys:

https://i.imgur.com/hM9XHJI.png - 7 days

https://i.imgur.com/6nkxh4Z.png - 11 days

Sales at:

10

11 (3x)

12 (3x)

13

10 quicksold, excluding 10.

Going with 11-13.