Sales 1-3:

Sold for $55, $60.79 & $60 on marketplace.tf

https://marketplace.tf/items/30647;5;u95

https://backpack.tf/item/6923226461 - No B/O

Couldn’t find the other two histories.

http://manic.tf/keyprice/?at=2018-06-11 - $55 / $1.94 = 28.35 keys

http://manic.tf/keyprice/?at=2018-07-21 - $60.79 / $1.95 = 31.17 keys

http://manic.tf/keyprice/?at=2018-09-02 - $60 / $1.88 = 31.91 keys

X = 32

X = 31

X = 28

Sale 4:

Sold for 26 keys

Seller: https://backpack.tf/profiles/76561198382654640#!/compare/1531958400/1532044800

Buyer: https://backpack.tf/profiles/76561198012523507#!/compare/1531785600/1532044800

https://backpack.tf/item/4227164914

X = 26

Sale 5:

Sold for 23 keys

Seller: https://backpack.tf/profiles/76561198337734785#!/compare/1535673600/1535760000

Buyer: https://backpack.tf/profiles/76561198309838525#!/compare/1535673600/1535760000

https://backpack.tf/item/4237090251

X = 23

Sale 6:

Bought from scrap.tf for 22 keys + 5 ref

Seller: https://backpack.tf/profiles/76561198135388328#!/compare/1535587200/1535673600

Buyer: https://backpack.tf/profiles/76561198327178564#!/compare/1522627200/1535760000

https://backpack.tf/item/7110587828

X = 22

Sale 7:

Sold for 22 keys

Seller: https://backpack.tf/profiles/76561198086076383#!/compare/1535328000/1535414400

Buyer: https://backpack.tf/profiles/76561198254431732#!/compare/1535414400/1536278400

https://backpack.tf/item/5302553435

X = 22

Sale 8:

Sold to a quickbuyer for 22 keys + 4 ref

Seller: https://backpack.tf/profiles/76561198061376237#!/compare/1528416000/1529798400

Buyer: https://backpack.tf/profiles/76561198342161127#!/compare/1529798400/1536451200

https://backpack.tf/item/4383540328

X = 22

Sale 9:

Sold for 21 keys

Seller: https://backpack.tf/profiles/76561198089976309#!/compare/1534723200/1534809600

Buyer: https://backpack.tf/profiles/76561198126725924#!/compare/1534723200/1534809600

https://backpack.tf/item/4383540328

X = 21

Other Sales:

https://backpack.tf/item/6884076416 (#1 & #2)

https://backpack.tf/item/5302553435 (#3 & #4)

https://backpack.tf/item/4455770543 (#5)

https://backpack.tf/item/4401849149 (#6 & #7)

https://backpack.tf/item/4347565465 (#8)

https://backpack.tf/item/4250666155 (#9)

https://backpack.tf/item/4237090251 (#10)

#1

Bulk for Scorching Tundra Top

https://backpack.tf/profiles/76561198152708934#!/compare/1529798400/1529884800

https://backpack.tf/profiles/76561198373161571#!/compare/1529712000/1529884800

#2

Sharked

https://backpack.tf/profiles/76561198373161571#!/compare/1529884800/1529971200

https://backpack.tf/profiles/76561198197739413#!/compare/1529884800/1529971200

#3

Probably SCM

https://backpack.tf/profiles/76561198089747205#!/compare/1529884800/1530144000

https://backpack.tf/profiles/76561198133644866#!/compare/1530230400/1531526400

#4

Untraceable

https://backpack.tf/profiles/76561198254431732#!/compare/1535673600/1536019200

https://backpack.tf/profiles/76561198150107313#!/compare/1535760000/1535846400

#5

Untraceable, probably sold for keys

https://backpack.tf/profiles/76561198313769156#!/compare/1531958400/1532131200

https://backpack.tf/profiles/76561198024867201#!/compare/1531958400/1532044800

#6

Untraceable

https://backpack.tf/profiles/76561198311498888#!/compare/1535932800/1536019200

https://backpack.tf/profiles/76561198125499317#!/compare/1535932800/1536105600

#7

Untraceable, most likely sold for the DBD Titanium Pillar

https://backpack.tf/profiles/76561198125499317#!/compare/1536105600/1536537600

https://backpack.tf/profiles/76561198264117106#!/compare/1535932800/1536105600

#8

Untraceable

https://backpack.tf/profiles/76561198337734785#!/compare/1530662400/1530748800

https://backpack.tf/profiles/76561198108853200#!/compare/1530576000/1530662400

#9

Sharked

https://backpack.tf/profiles/76561197994288846#!/compare/1530403200/1531612800

https://backpack.tf/profiles/76561198041429090#!/compare/1531526400/1531872000

#10

Sold for Strange Miami Nights Pithy Professional

https://backpack.tf/profiles/76561198309838525#!/compare/1536192000/1536278400

https://backpack.tf/profiles/76561198121933439#!/compare/1536105600/1536278400

Sellers:

https://i.imgur.com/q34M3Mg.png

https://backpack.tf/item/6923226461 - 28 keys

https://backpack.tf/item/5302553435 - 30 keys

https://backpack.tf/item/4237090251 - 30 keys

https://backpack.tf/item/4401849149 - 40 keys

https://backpack.tf/item/6884076416 - 330 keys

Sales at:

21

22 (3x)

23

26

28

31

32

Excluding 31 and 32 due to the sales and sellers for cheaper.

Going with 21-28.