Sale 1:

Sold for Searing Plasma Toy Tailor (25.5) + 1 key

http://www.tf2outpost.com/trade/28692285 - No visible B/O

Seller: http://backpack.tf/profiles/76561198011321852#!/compare/1483228800/1483315200

Buyer: http://backpack.tf/profiles/76561198083000445#!/compare/1483228800/1483315200

X = 27

Sale 2:

Sold for Green Confetti Texas Ten-Gallon (25) + 2 keys + 10 ref (<0.5)

http://www.tf2outpost.com/trade/28694648 - B/O of 27

Seller: http://backpack.tf/profiles/76561198083000445#!/compare/1483228800/1483315200

Buyer: http://backpack.tf/profiles/76561198295529541#!/compare/1483315200/1483660800

X = 27

Sale 3:

Sold for 26 keys

No outpost

Seller: http://backpack.tf/profiles/76561198108148076#!/compare/1482796800/1482883200

Buyer: http://backpack.tf/profiles/76561198039303724#!/compare/1482796800/1483056000

X = 26

Sale 4:

Sold for 26 keys

http://www.tf2outpost.com/trade/28656832 - Deleted B/O

Seller: http://backpack.tf/profiles/76561198141170332#!/compare/1481500800/1481587200

Buyer: http://backpack.tf/profiles/76561198182681385#!/compare/1481500800/1481587200

X = 26

Sale 5:

Sold for Infernal Flames Deep Fried Desire (25)

http://www.tf2outpost.com/trade/28693255 - B/O of 25

Seller: http://backpack.tf/profiles/76561198240421974#!/compare/1483315200/1483401600

Buyer: http://backpack.tf/profiles/76561198268163891#!/compare/1483315200/1483401600

X = 25

Sale 6:

Sold for 25 keys

http://www.tf2outpost.com/trade/28695362 - B/O of 25

Seller: http://backpack.tf/profiles/76561198057671085#!/compare/1483660800/1483747200

Buyer: http://backpack.tf/profiles/76561198255115346#!/compare/1483574400/1483747200

X = 25

Sale 7:

Sold for Orbiting Fire Defiant Spartan (Mini at 16 below) + 7 keys + ~2 keys in items

http://www.tf2outpost.com/trade/28610126 - B/O of 28

Seller: http://backpack.tf/profiles/76561198156255538#!/compare/1479427200/1479513600

Buyer: http://backpack.tf/profiles/76561198218566031#!/compare/1479513600/1479600000

X = 25

Sale 8:

Sold for 24 keys

No outpost

Seller: http://backpack.tf/profiles/76561198047208911#!/compare/1483142400/1483228800

Buyer: http://backpack.tf/profiles/76561198240421974#!/compare/1483142400/1483315200

X = 24

Sale 9:

Sold for Spectral Swirl Deep Fried Desire (23)

No outpost

Seller: http://backpack.tf/profiles/76561198125760599#!/compare/1483315200/1483401600

Buyer: http://backpack.tf/profiles/76561198125791160#!/compare/1483228800/1483315200

X = 23

Sale 10:

Sold for Smoking Brainiac Hairpiece

No outpost

Seller: http://backpack.tf/profiles/76561198218566031#!/compare/1479600000/1479772800

Buyer: http://backpack.tf/profiles/76561198047208911#!/compare/1479686400/1479772800

May be better to update the Hairpiece with this sale, seeing as it is outdated, with sellers for much less than its current price.

Orbiting Fire Defiant Spartan Mini:

http://backpack.tf/suggestion/588f2fa6c4404572a93fef6a

Sellers:

30 keys:

http://i.imgur.com/jSQ1M76.png - 27 days

http://backpack.tf/u/76561198125791160

32 keys:

http://www.tf2outpost.com/trade/28609336 - 2 months

http://backpack.tf/u/76561198017054389

Sales at:

23

24

25 (3x)

26 (2x)

27 (2x)

Going with 23-27.