Using last month.

Sale 1:

Sold for Grail Battin’ (Mini at 5.5 below)

No outpost

Seller: https://backpack.tf/profiles/76561198041855608#!/compare/1524441600/1524787200

Buyer: https://backpack.tf/profiles/76561198267448829#!/compare/1524009600/1524787200

X = 5.5

Sale 2:

Sold with ~7.33 ref for 5 keys

https://i.imgur.com/TI4XqCt.png

Seller: https://backpack.tf/profiles/76561198048851745#!/compare/1526688000/1526774400

Buyer: https://backpack.tf/profiles/76561198328909298#!/compare/1526688000/1526774400

X = 4.5

Holy Grail Battin’ a Thousand Mini:

Sale 1:

Sold for 6 keys

Seller: https://backpack.tf/profiles/76561198305676157#!/compare/1525392000/1525478400

Buyer: https://backpack.tf/profiles/76561198346618954#!/compare/1525392000/1525478400

Bot.tf confirms: https://i.imgur.com/EdNe4p5.png

X = 6

Sale 2:

Sold for 6 keys

Seller: https://backpack.tf/profiles/76561198305676157#!/compare/1525305600/1525392000

Buyer: https://backpack.tf/profiles/76561198025934379#!/compare/1525305600/1525392000

Bot.tf confirms: https://i.imgur.com/EdNe4p5.png

X = 6

Sale 3:

Sold to a bot for 5 keys + 1 ref

Seller: https://backpack.tf/profiles/76561198374299210#!/compare/1524960000/1526601600

Buyer: https://backpack.tf/profiles/76561198305676157#!/compare/1525219200/1525305600

Bot.tf confirms: https://i.imgur.com/EdNe4p5.png

X = 5

Sale 4:

Sold to a bot for 5 keys + 1 ref

Seller: https://backpack.tf/profiles/76561198451665899#!/compare/1525046400/1525132800

Buyer: https://backpack.tf/profiles/76561198305676157#!/compare/1525046400/1525132800

Bot.tf confirms: https://i.imgur.com/EdNe4p5.png

X = 5

Taking 5.5. Will do a full suggestion once I get up to it.

Sellers:

22 keys:

http://www.tf2outpost.com/trade/29457900

Offers:

http://www.tf2outpost.com/trade/29491922

Sales at:

4.5

5.5

Going with 4.5-5.5.