Suggestion 5. Squad 1.

Sales

Sold for 8 keys

https://backpack.tf/item/7956733203

https://gyazo.com/5685ae5dc4b9ab9adffe287bd00c845e

Sold for Collector's Festivized Professional Killstreak Reserve Shooter

https://backpack.tf/profiles/76561198073382916#!/compare/1601424000/1601942400

https://backpack.tf/profiles/76561198869423410#!/compare/1601769600/1601856000

Mini for Reserve Shooter:

32.83/3.02 = 10.87 rounding to 11 keys

https://steamcommunity.com/market/listings/440/Collector%27s%20Festivized%20Professional%20Killstreak%20Reserve%20Shooter?filter=%3E

$32.83 on November 11.

https://steamcommunity.com/market/listings/440/Mann%20Co.%20Supply%20Crate%20Key

Keys were averaged at 3.02 on November 11 .

Marketplace sales

https://marketplace.tf/items/tf2/30039;5;u62

Dec 5 16.99, $16.99 / $1.76 = 9.5 keys

https://manic.tf/keyprice/?at=2020-12-05

Dec 13 16.99, $16.99 / $1.92 = 9 keys

https://manic.tf/keyprice/?at=2020-12-13

Summary

Sales at 8, 9, 9.5, and 11.

Conclusion

Going with 8-11 here.