History 1: https://backpack.tf/item/9221812611

18 keys (only 18 of the 29 keys in seller's compare match and 18 keys match in buyer's compare too)

https://backpack.tf/profiles/76561198188093413#!/compare/1607472000/1607558400

https://backpack.tf/profiles/76561198090785419#!/compare/1607472000/1607558400

History 2: https://backpack.tf/item/9164642865

30 keys:

https://backpack.tf/profiles/76561198125791160#!/compare/1606521600/1606608000

https://backpack.tf/profiles/76561198065805500#!/compare/1606608000/1606953600

History 3: https://backpack.tf/item/9148694629

Untraceable:

https://backpack.tf/profiles/76561198000980532#!/compare/1606694400/1607644800

https://backpack.tf/profiles/76561198091502579#!/compare/1606694400/1606780800

Sold on marketplace.tf, look below

only 5 keys match:

https://backpack.tf/profiles/76561198055400213#!/compare/1608336000/1608422400

https://backpack.tf/profiles/76561198081491001#!/compare/1608422400/1608508800

20 keys 2 ref, ~20 keys (the same matches in the buyer's compare, the rest went to the Rocket Jockey)

https://backpack.tf/profiles/76561198081491001#!/compare/1609286400/1609372800

https://backpack.tf/profiles/76561198097271466#!/compare/1609286400/1609372800

28 keys:

https://backpack.tf/profiles/76561198097271466#!/compare/1610582400/1610668800

https://backpack.tf/profiles/76561198133392504#!/compare/1610496000/1610668800

Sold for a Vivid Plasma Smoking Skid Lid + 8 keys

https://backpack.tf/profiles/76561198133392504#!/compare/1610928000/1611014400

https://backpack.tf/profiles/76561198039846030#!/compare/1611014400/1611100800

Lid mini at 28 keys https://backpack.tf/suggestion/602ff832489bf8780a35aff8

28+8=36

Buyout was 40, doesn't cap https://gladiator.tf/listings/600587f16b420f90ba9341d8

Sold for a Phosphorous Shooter's Sola Topi:

https://backpack.tf/profiles/76561198039846030#!/compare/1612051200/1612224000

https://backpack.tf/profiles/76561198055622215#!/compare/1612137600/1612224000

Using there beacuse the Topi doesn't have any other usable sales https://backpack.tf/item/1667645863

History 4: https://backpack.tf/item/9141222380

Untraceable:

https://backpack.tf/profiles/76561198831477246#!/compare/1608681600/1608768000

https://backpack.tf/profiles/76561198053044333#!/compare/1603238400/1610150400

Untraceable, none of the pure in buyer's compare matches:

https://backpack.tf/profiles/76561198053044333#!/compare/1610409600/1610496000

https://backpack.tf/profiles/76561198118534054#!/compare/1610496000/1610582400

Marketplace.tf sales: https://marketplace.tf/items/tf2/31117;5;u9

December 4: $49.99/1.76=28.4 ~28 keys

December 10: $69.99/1.81=38.67 ~39 keys

Unsolds: 1 at 40 keys for 1 month https://backpack.tf/item/9141222380

Sales at 18, 20, 28, 28, 30, 36, 39

Given the buyers up to 23.31-25 keys, 18-20 looks low. The sales at 36 and 39 look out of place too. 39 was Marketplace.tf and 36 is an item sale that doesn't cap.

To balance out the range and based on mod's advice, going 28-30