Resuggestion, Thanks to Foamy for the info!

Sale 1:

https://backpack.tf/profiles/76561198069337273#!/compare/1546905600/1548460800

https://backpack.tf/profiles/76561198281266423#!/compare/1546905600/1546992000

SCM

Sale 2:

https://backpack.tf/profiles/76561198024867201#!/compare/1545436800/1545523200

https://backpack.tf/profiles/76561198797619856#!/compare/1545523200/1546041600

Keys

Sale 3:

https://backpack.tf/profiles/76561198797619856#!/compare/1546732800/1547424000

https://backpack.tf/profiles/76561198168863803#!/compare/1547337600/1547424000

Sold with ~2 keys in sweets for KaW Modest Scrap

Scrap Mini:

https://backpack.tf/suggestion/5c85cf7967807205a304c278

Suggestion for 19.5 keys

Total is 17.5 keys

Sale 4:

https://backpack.tf/profiles/76561198168863803#!/compare/1548979200/1549065600

https://backpack.tf/profiles/76561198259469502#!/compare/1549065600/1549152000

Sold for 16 keys

Sale 5:

https://backpack.tf/profiles/76561198259469502#!/compare/1549411200/1549584000

https://backpack.tf/profiles/76561198129123592#!/compare/1549411200/1549584000

Untrace

Sale 6:

https://backpack.tf/profiles/76561198129123592#!/compare/1552003200/1552089600

https://backpack.tf/profiles/76561198062249974#!/compare/1551916800/1552089600

Bulky

Sale 7:

https://backpack.tf/profiles/76561198201106142#!/compare/1549411200/1549497600

https://backpack.tf/profiles/76561198350807742#!/compare/1549324800/1549497600

Sold for 15 keys + ~1 key in sweets

Total is 16 keys

Sale 8:

https://backpack.tf/profiles/76561198114402400#!/compare/1544400000/1544486400

https://backpack.tf/profiles/76561198254285639#!/compare/1544400000/1544486400

Bulk

Sale 9:

https://backpack.tf/profiles/76561198254285639#!/compare/1544572800/1544659200

https://backpack.tf/profiles/76561198130359983#!/compare/1544054400/1544745600

Sold for ~15 keys

Sale 10:

https://backpack.tf/profiles/76561198130359983#!/compare/1546041600/1546473600

https://backpack.tf/profiles/76561198256394935#!/compare/1545696000/1546905600

Sold for 18 keys

Sale 11:

https://backpack.tf/profiles/76561198256394935#!/compare/1550966400/1551052800

https://backpack.tf/profiles/76561198119013032#!/compare/1550966400/1551052800

Bulk

Sale 12:

https://backpack.tf/profiles/76561198065409820#!/compare/1545696000/1546560000

https://backpack.tf/profiles/76561198074625962#!/compare/1546387200/1546473600

Could be bulk? or ~15?

Sale 13:

https://backpack.tf/profiles/76561198074625962#!/compare/1546732800/1546905600

https://backpack.tf/profiles/76561198020054731#!/compare/1546819200/1546905600

Sold for 15 keys

Sale 13:

https://backpack.tf/profiles/76561198020054731#!/compare/1546992000/1547078400

https://backpack.tf/profiles/76561198205383525#!/compare/1546905600/1547078400

Sold for 16 keys

Sale 14:

https://backpack.tf/profiles/76561198080179568#!/compare/1546819200/1546905600

https://backpack.tf/profiles/76561198079098551#!/compare/1546300800/1546905600

Used there

Sale 15:

https://backpack.tf/profiles/76561198079098551#!/compare/1548115200/1548633600

https://backpack.tf/profiles/76561197992322606#!/compare/1548460800/1548547200

Sold with Grail Schaudenfraude for CTFL Tyrant

End up slightly bulky

Sale 16:

https://backpack.tf/profiles/76561197992322606#!/compare/1551571200/1552176000

https://backpack.tf/profiles/76561198375430785#!/compare/1552003200/1552089600

Sold for Blizzardy Honcho

Honcho Mini:

https://backpack.tf/suggestion/5c85d6b5d381726d6d7562b8

Suggestion for 18.5 keys

Sale 17:

https://backpack.tf/profiles/76561198375430785#!/compare/1552003200/1552089600

https://backpack.tf/profiles/76561198224348988#!/compare/1552003200/1552089600

Sold for 14 keys

Sale 18:

https://backpack.tf/profiles/76561198224348988#!/compare/1552089600/1552176000

https://backpack.tf/profiles/76561198075099319#!/compare/1552089600/1552176000

Sold for DBD Big Country

Use there

Sale 19:

https://backpack.tf/profiles/76561198312583107#!/compare/1546560000/1546646400

https://backpack.tf/profiles/76561198254285639#!/compare/1546560000/1546646400

Keys

Sale 20:

https://backpack.tf/profiles/76561198254285639#!/compare/1547683200/1547769600

https://backpack.tf/profiles/76561198163470512#!/compare/1547596800/1547769600

Sold for ~18 keys in items

Sale 21:

https://backpack.tf/profiles/76561198163470512#!/compare/1547856000/1547942400

https://backpack.tf/profiles/76561198008994962#!/compare/1547424000/1547856000

Bulk

Sale 22:

https://backpack.tf/profiles/76561198008994962#!/compare/1551225600/1551484800

https://backpack.tf/profiles/76561198191538393#!/compare/1551484800/1551571200

Sold for 17 keys

Sale 23:

https://backpack.tf/profiles/76561198191538393#!/compare/1551744000/1551916800

https://backpack.tf/profiles/76561198864018460#!/compare/NaN/1551916800

Transfer

Sale 24:

https://backpack.tf/profiles/76561198079639072#!/compare/1544572800/1552176000

https://backpack.tf/profiles/76561198280357510#!/compare/1552089600/1552176000

Sold for DP Headsplitter

Head Splitter Mini:

https://backpack.tf/suggestion/5c85dea9d3817270e93902df

Suggestion for 13.5

Total sales @:

13.5, 14, 15, 15, 16, 16, 16, 17, 17.5, 18, 18, 18.5 keys

Foamy's Part:

14 qsed and at least one of your 15 sales went really fast here as well. I would go 15-19 here and use this on the splitter instead. That has a couple of ignored high sales, perhaps this puts that in perspective.

Taking 15 - 19 keys