Never made an unusual suggestion, so advice would help.

Sale 1: http://www.tf2outpost.com/trade/25735608

Sold for a Circling Heart Magistrate's Mullet (16-18 keys. Taking 17 keys)

http://backpack.tf/profiles/76561198120594001?time=1429167600 (April 16th)

http://backpack.tf/profiles/76561198120594001?time=1429340400 (April 18th)

Hist of DP Barnstormer: http://backpack.tf/item/2566763873

Hist of CH Mullet: http://backpack.tf/item/668133205

17*0.9 = ~15 keys

Sale 2: No trade link

Sold for S. Spec KS Widowmaker (1.73) and Bubbling Rather Festive Tree (18)

http://backpack.tf/profiles/76561198094126587?time=1429772400 (April 23rd)

http://backpack.tf/profiles/76561198094126587?time=1429945200 (April 25th)

Hist of Bubbling Tree: http://backpack.tf/item/447596203

Hist of Spec KS Widowmaker: http://backpack.tf/item/2583245040

18*0.9 + 1.73*0.9 = ~18 keys

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Mini for Bubbling Rather Festive Tree:

Sold for an Aces High Desert Marauder (20 keys)

http://backpack.tf/profiles/76561198047295453?time=1425628800 (March 6th)

http://backpack.tf/profiles/76561198047295453?time=1425884400 (March 9th)

Hist for AH Marauder: http://backpack.tf/item/2182112009

20*0.9 = 18 keys

Mini for S. Spec KS Widowmaker:

SCM sales for April 24: http://steamcommunity.com/market/listings/440/Strange%20Specialized%20Killstreak%20Widowmaker

3.94

3.93

4.09

4.50

Average: 4.12 SCM / 2.38 = ~1.73 keys