Resuggestion, thanks to Shuffle Spy for the info!

CLEAN SALES:

Sale 1:

https://backpack.tf/profiles/76561198122295764#!/compare/1588291200/1588377600

https://backpack.tf/profiles/76561198236030772#!/compare/1588204800/1588291200

untrace

sale 2:

https://backpack.tf/profiles/76561198236030772#!/compare/1588291200/1588377600

https://backpack.tf/profiles/76561198014029735#!/compare/1588291200/1588377600

Sold for Aussie Sniper(~27)

https://bot.tf/stats/listings/4WXNOPWZ

B/O of 33 keys

sale 3:

https://backpack.tf/profiles/76561198006544512#!/compare/1582156800/1582243200

https://backpack.tf/profiles/76561198362008411#!/compare/1582156800/1582243200

Sold for 25 keys

Sale 4:

https://backpack.tf/profiles/76561198362008411#!/compare/1584230400/1584316800

https://backpack.tf/profiles/76561198131633162#!/compare/1584144000/1584230400

Bulk

sale 5:

https://backpack.tf/profiles/76561198131633162#!/compare/1588377600/1588636800

https://backpack.tf/profiles/76561198135811642#!/compare/1582848000/1589068800

Sold for 25 keys

sale 6:

https://backpack.tf/profiles/76561197999507606#!/compare/1582761600/1583193600

https://backpack.tf/profiles/76561198850274253#!/compare/1582675200/1582761600

QS

sale 7:

https://backpack.tf/profiles/76561198850274253#!/compare/1583539200/1583625600

https://backpack.tf/profiles/76561198806737446#!/compare/1583366400/1583712000

Untrace

sAle 8:

https://marketplace.tf/items/tf2/538;5;u36

$65 / $1.69 = 38.46 keys

can't tell if duped sale or not, not using.

Total sales @:

25, 25, 27 keys

================================

DUPED SALES:

Sale 1:

https://backpack.tf/profiles/76561198281398809#!/compare/1585958400/1589241600

https://backpack.tf/profiles/76561198293092116#!/compare/1587513600/1588291200

untrace

sale 2:

https://backpack.tf/profiles/76561198214308952#!/compare/1585094400/1585180800

https://backpack.tf/profiles/76561198994857134#!/compare/1585094400/1585180800

Can trace Aussie Blut

sale 3:

https://backpack.tf/profiles/76561198994857134#!/compare/1585094400/1585180800

https://backpack.tf/profiles/76561198095236132#!/compare/1585008000/1585180800

Sold with Smoking Hermes for G Fetti Yellow(29)

bulky

sale 4:

https://backpack.tf/profiles/76561198095236132#!/compare/1585008000/1585180800

https://backpack.tf/profiles/76561198069302272#!/compare/1576540800/1585180800

Sold with 5 keys for Warp Pride

use there

https://bot.tf/stats/listings/4O99QQWW

B/O of 33 keys

sale 5:

https://backpack.tf/profiles/76561198069302272#!/compare/1585180800/1585267200

https://backpack.tf/profiles/76561198026952339#!/compare/1585180800/1585267200

Sold for CTFL Screamin + C9 Guad + 10 keys

https://bot.tf/stats/listings/M0OON0PZ

B/O of 30 keys, easily caps by buyers.

sale 6:

https://backpack.tf/profiles/76561198026952339#!/compare/1585267200/1585353600

https://backpack.tf/profiles/76561198316317677#!/compare/1585267200/1585353600

Sold for DBD gutten + 2 keys

use there

https://bot.tf/stats/listings/MGLLWD8W

B/O of 30 keys

sale 7:

https://backpack.tf/profiles/76561198316317677#!/compare/1585440000/1585526400

https://backpack.tf/profiles/76561198394148072#!/compare/1585440000/1585526400

Sold for KaW Bomber(22.5)

https://bot.tf/stats/listings/Y799RRRK

B/O of 33 keys

sale 8:

https://backpack.tf/profiles/76561198394148072#!/compare/1585526400/1585612800

https://backpack.tf/profiles/76561198340829257#!/compare/1585612800/1585699200

Sold for PE Shutter(31) + ~1 key in sweets

Total is 32 keys

https://bot.tf/stats/listings/M0OO6PDE

B/O of 40 keys

sale 9:

https://backpack.tf/profiles/76561198340829257#!/compare/1585958400/1586044800

https://backpack.tf/profiles/76561198409284313#!/compare/1585872000/1586044800

Sold with 1 key for Miami Ritzy

use there

https://bot.tf/stats/listings/4WXQJNWN

B/O of 40 keys

Total sales @:

23, 30, 32 keys

=====================

TOTAL TOTAL SALES @:

23, 25, 25, 27, 30, 32, 38 keys

Shuffle's Part:

The Shutterbug is outdated. Its 2 sales aren't great though.

https://backpack.tf/profiles/76561198394148072#!/compare/1585612800/1585699200 - 19 Keys in Unusuals

https://backpack.tf/profiles/76561198251524922#!/compare/1585612800/1585699200 - Quicksold for 20 Keys + ~1 Key of Items

The 30 sale is realistically ~35+ before being capped, so the duped sales are decently far apart.

Additionally, since the person who paid the Guten + 2 (still ~30 total even if you had used the Guten here) sold for 22.5, I'd exclude both.

Narrowing the range to 25 - 27 will work.