Resuggestion, thx K1ng

History 1: https://backpack.tf/item/7957370525

Marketplace.tf

History 2: https://backpack.tf/item/7956972499

Untraceable:

https://backpack.tf/profiles/76561198248509344#!/compare/1618272000/1618444800

https://backpack.tf/profiles/76561198209249621#!/compare/1618358400/1618704000

7 keys 31 ref match, ~7.5 keys, sold to a quickbuyer:

https://backpack.tf/profiles/76561198209249621#!/compare/1618272000/1618358400

https://backpack.tf/profiles/76561198002757046#!/compare/1618272000/1618358400

Sold for 10 keys 4 ref in ~1 day:

https://backpack.tf/profiles/76561198002757046#!/compare/1618272000/1618358400

https://backpack.tf/profiles/76561198080179568#!/compare/1618272000/1618358400

Then went to Marketplace.tf

History 3: https://backpack.tf/item/3726265817

Actually ~16 keys (tkx K1ng for correcting this):

https://backpack.tf/profiles/76561199106217370#!/compare/1619740800/1619827200

https://backpack.tf/profiles/76561198871795266#!/compare/1619654400/1619827200

https://gladiator.tf/listings/608a91d3ccbf26cf5fb290da

https://backpack.tf/profiles/76561198871795266#!/compare/1619654400/1619827200 ----- the 14 keys seen here match

https://backpack.tf/item/9716869145 ---- an extra key that came from selling the Hungover

https://gladiator.tf/listings/608cae9670acfcc328513004 ----- the ref also came from the Hungover it seems

Marketplace.tf: https://marketplace.tf/items/tf2/30136;5;u58

May 15: $29.9/2=14.95 ~15 keys

June 7: $31.99/1.96=16.32 ~16 keys

None of these had buyouts

Sales at 7.5, 10, 15, 16, 16

Taking mod's advice and going with 15-16 keys