I was working on this along-side the RA War Pig but heyho you took that.

This is what I got for this:

Sale 1)

https://backpack.tf/profiles/76561198027063074#!/compare/1588118400/1588204800 - Using there

Sale 2)

https://backpack.tf/profiles/76561198118157202#!/compare/1587340800/1587427200

https://backpack.tf/profiles/76561198027063074#!/compare/1587427200/1587513600 - Sold for a Duped Circling Heart Blighted Beak (320) + A Cloud 9 Horrific Headsplitter (21) + A Max's Severed Head (~17.5) = (359) Keys

Buyout was 400 Keys - https://bot.tf/stats/listings/4J96P3QV

Mini for Beak:

https://backpack.tf/profiles/76561198118157202#!/compare/1587600000/1587686400 + https://backpack.tf/profiles/76561197967470975#!/compare/1587686400/1587772800 - Sold for less than 100 Keys?

https://backpack.tf/profiles/76561198129552058#!/compare/1579478400/1579564800 - Sold with 5 Keys for a Duped Burning Flames Blighted Beak (420) = 415 Keys - Caps at Buyout of 320 Keys - https://bot.tf/stats/listings/4OVNQX6V

Micro for Burning Beak:

https://backpack.tf/profiles/76561198076040443#!/compare/1586131200/1586217600 - Bulky

https://backpack.tf/profiles/76561198061779536#!/compare/1581638400/1581724800 - Low

https://backpack.tf/profiles/76561198053747026#!/compare/1583712000/1583798400 - Sold for a Kill-a-Watt Head Prize (350) + A Purple Energy Tipped Lid (50) + A Haunted Ghosts Glengarry Bonnet (25, using unsold) + A Haunted Ghosts Slo-Poke (40, using unsold) + A Haunted Ghosts Harmburg (~40) = 505, Caps at 420 - https://bot.tf/stats/listings/4O9O6Q7V

Sale 3)

https://backpack.tf/profiles/76561198000247762#!/compare/1586563200/1586995200 - Sold with a Purple Energy Rotation Sensation for a Something Burning This Way Comes Duck Billed Hatypus (270) + 10 Keys

Buyout was 350 Keys - https://bot.tf/stats/listings/Y9QLQV3D

Sale 4)

https://backpack.tf/profiles/76561198033378852#!/compare/1585699200/1585785600

https://backpack.tf/profiles/76561198000247762#!/compare/1585612800/1585785600 - Sold for a Smoking Captain Cardbeard Cutthroat (238) Keys

Buyout was 600 Keys - https://bot.tf/stats/listings/4P0VPD2E

Sale 5)

https://backpack.tf/profiles/76561198953695435#!/compare/1585612800/1585785600

https://backpack.tf/profiles/76561198033378852#!/compare/1585612800/1585699200 - Untrace

Sale 6)

https://backpack.tf/profiles/76561197971174166#!/compare/1585008000/1585094400

https://backpack.tf/profiles/76561198953695435#!/compare/1584835200/1585094400 - Untrace

Sale 7)

https://backpack.tf/profiles/76561198083122789#!/compare/1584403200/1584576000 - Sold for a Duped Sunbeams Mining Light (>127, Thux's buy order is 10% less for dupes) + 202 Keys = 329 Keys, Caps at Buyout

Buyout was (320) Keys - https://bot.tf/stats/listings/4WXPDG5N

Maybe not much use or maybe it helps idk, I managed to Mini the Duck Hatypus sale so that can be used here instead, might help exclude a sale and tighten the range. Only thing is PE Rotation needs a Mini

https://marketplace.tf/items/tf2/315;5;u19 - The duped Circling Heart Blighted Beak sold again for $650 (327 Keys)

https://backpack.tf/item/269699887 - The 327 sale history

https://imgur.com/a/KN4aDxC - 26 day seller at 300 Keys makes 327 seem high

Factoring in the Max's, I would make this 300 - 320 Keys.