Sale 1:

Sold for Cloud 9 Oiled Baker Boy (15.5)

No outpost

Seller: http://backpack.tf/profiles/76561198112281935#!/compare/1476316800/1476403200

Buyer: http://backpack.tf/profiles/76561198253554923#!/compare/1476316800/1476403200

X = 16

Sale 2:

Quicksold for 12 keys

No outpost

Seller: http://backpack.tf/profiles/76561198174203179#!/compare/1476489600/1476576000

Buyer: http://backpack.tf/profiles/76561198150645469#!/compare/1476489600/1476576000

X = 12

Sale 3:

Sold with ~4 keys in stranges for Peace Sign Engineer’s Cap (14.5)

No outpost

Seller: http://backpack.tf/profiles/76561198150645469#!/compare/1476489600/1476576000

Buyer: http://backpack.tf/profiles/76561198144745947#!/compare/1476230400/1476576000

X = 11

Sale 4:

Sold for 11 keys

No outpost

Seller: http://backpack.tf/profiles/76561198112612121#!/compare/1477526400/1477612800

Buyer: http://backpack.tf/profiles/76561198164663815#!/compare/1477440000/1477612800

X = 11

Sale 5:

Sold for 9 keys + ~2 keys in ref

http://www.tf2outpost.com/trade/28569886 - B/O of 11

Seller: http://backpack.tf/profiles/76561198164663815#!/compare/1478563200/1478649600

Buyer: http://backpack.tf/profiles/76561198032656960#!/compare/1478563200/1478649600

X = 11

Sale 6:

Sold for Strange Terror-Watt Sola Topi (Mini at 11 below)

http://www.tf2outpost.com/trade/28558949 - B/O of 14

Seller: http://backpack.tf/profiles/76561198144745947#!/compare/1477008000/1477267200

Buyer: http://backpack.tf/profiles/76561198232041512#!/compare/1477094400/1477180800

X = 11

Sale 7:

Sold in about a day for 9 keys + 4.33 ref?

No outpost

Seller: http://backpack.tf/profiles/76561198253554923#!/compare/1476489600/1476576000

Buyer: http://backpack.tf/profiles/76561198174203179#!/compare/1476489600/1476576000

X = 9

Strange Terror-Watt Topi Mini:

Sold with ~1 key in items for Miami Nights Dread Knot (Mini at 12 below)

Seller: http://backpack.tf/profiles/76561198257058049#!/compare/1478217600/1478304000

Buyer: http://backpack.tf/profiles/76561198146457808#!/compare/1477958400/1478563200

X = 11

Miami Nights Dread Knot Mini:

Seller at 12 keys for 5 days:

http://i.imgur.com/wno45sZ.png

http://backpack.tf/u/76561198002757046

http://www.tf2outpost.com/trade/28610377

Sellers:

16 keys:

http://i.imgur.com/YkW86e1.png

http://backpack.tf/u/76561198032656960

Sales at:

16

12

11 (4x)

9

16 looks like an outlier, with the abundance of sales for lower

9 is too low, due to the buyer on the classifieds for 9 keys

Going with 11-12