Resuggestion, thanks to Foamy & Mindacos for the info!

Sale 1:

https://backpack.tf/profiles/76561198313538268#!/compare/1542585600/1542672000

https://backpack.tf/profiles/76561198091133177#!/compare/1542585600/1542672000

Some amount of keys, can't accurately trace

Sale 2:

https://backpack.tf/profiles/76561198091133177#!/compare/1542585600/1542672000

https://backpack.tf/profiles/76561197993708178#!/compare/1540944000/1542672000

Bulk

Sale 3:

https://backpack.tf/profiles/76561198134923092#!/compare/1544140800/1544313600

https://backpack.tf/profiles/76561197993708178#!/compare/1543968000/1544227200

Sold for GBH Fez(38) + ~1 key in sweets

Total is 39 keys

Sale 4:

https://backpack.tf/profiles/76561198080180196#!/compare/1456128000/1543190400

https://backpack.tf/profiles/76561198006544512#!/compare/1543104000/1543190400

Sold for 31 keys + negligible sweets

Sale 5:

https://backpack.tf/profiles/76561198006544512#!/compare/1547942400/1548028800

https://backpack.tf/profiles/76561198076804761#!/compare/1547942400/1548028800

Sold for 35 keys + negligible sweets

Sale 6:

https://backpack.tf/profiles/76561198129205357#!/compare/1541980800/1542067200

https://backpack.tf/profiles/76561198832639251#!/compare/1541894400/1541980800

Bulk

Sale 7:

https://backpack.tf/profiles/76561198832639251#!/compare/1542412800/1542499200

https://backpack.tf/profiles/76561198376090993#!/compare/1542412800/1542499200

Sold for 35 keys

Sale 8:

https://backpack.tf/profiles/76561198376090993#!/compare/1545004800/1545091200

https://backpack.tf/profiles/76561198276326357#!/compare/1544832000/1545004800

Sold 33 keys (ID Match)

Sale 9:

https://backpack.tf/profiles/76561198276326357#!/compare/1545177600/1545264000

https://backpack.tf/profiles/76561198832639251#!/compare/1545177600/1545264000

Sold for 31 keys + ref?

Sale 10:

https://backpack.tf/profiles/76561198832639251#!/compare/1546214400/1546300800

https://backpack.tf/profiles/76561198132948038#!/compare/1546300800/1546646400

Sold for 36 keys

Sale 11:

https://backpack.tf/profiles/76561198132948038#!/compare/1548460800/1548547200

https://backpack.tf/profiles/76561198443489337#!/compare/1548460800/1548547200

Sold for 28 keys?

Sale 12:

https://backpack.tf/profiles/76561198443489337#!/compare/1548720000/1548806400

https://backpack.tf/profiles/76561198063814565#!/compare/1548720000/1548806400

Bulky

Sale 13:

https://marketplace.tf/items/180;5;u17

Sold for 75 USD

Keys at 1.73 USD

Total is 43.35 keys

Total sales @:

31, 31, 33, 35, 35, 36, 39, 43.35 keys

despite weird sales from 7 to 11, most supports a range.

Buyers up to ~32 keys,

Sellers at 49 keys

Mindacos' Part:

43 is 100% an outlier

the 33/fez sale was for 33 pure, IDs match

Taking 33 -39 keys