Finally got around to doing this.

Can I hit 100% again?

probably not since I just mentioned 100%

Sold for an Orbiting Fire Little Buddy(10 Keys with Overpay)

http://backpack.tf/profiles/76561198119113583?time=1429340400 -> http://backpack.tf/profiles/76561198119113583?time=1429426800

Sold for a Nuts & Bolts Officer's Ushanka(8 Keys with Overpay) and ~2 Keys in Sweets(10 Keys total)

http://backpack.tf/profiles/76561198131703086?time=1429811895 -> http://backpack.tf/profiles/76561198131703086?time=1429945200

http://backpack.tf/profiles/76561198085992890?time=1429945200 -> http://backpack.tf/profiles/76561198085992890?time=1430031600

Sold for a Smoking Pyro's Boron Beanie(10 Keys with Overpay)

http://backpack.tf/profiles/76561198122536664?time=1424813952 -> http://backpack.tf/profiles/76561198122536664?time=1426575600

Sold with ~3 Keys in Sweets for a Blizzardy Storm Pyro's Beanie(12 Keys with Overpay)(9 Keys total)

http://backpack.tf/profiles/76561198078227728?time=1429081200 -> http://backpack.tf/profiles/76561198078227728?time=1429167600

Sold for a Nuts & Bolts Big Elfin' Deal(9 Keys with Overpay)

http://backpack.tf/profiles/76561198157431464?time=1429081200 -> http://backpack.tf/profiles/76561198157431464?time=1429340400

Sales seem to fit, 9-10 Keys should be fine.

Additional Proof/Counter-Proof/Constructive Criticism/Feedback is always appreciated.