14 is definitely not working out.

Unsold for 14 keys

http://www.tf2outpost.com/trade/8658361 - 1 day

http://www.tf2outpost.com/trade/8569227 - 5 days

http://www.tf2outpost.com/trade/8525820 - a week (Had 1 buyer who was willing to buy it. Seller told buyer that he/she has 2 s.f. huntsman but as you can check his/her bp, he/she still has 2 of these which means none of them were sold)

http://www.tf2outpost.com/trade/8554921 - 6 days

http://www.tf2outpost.com/trade/8624991 - 2 days

http://www.tf2outpost.com/trade/8212632 - 3 weeks

http://www.tf2outpost.com/trade/8555428 - 6 days

http://www.tf2outpost.com/trade/8539212 - 6 days

http://www.tf2outpost.com/trade/8578697 - 5 days

http://www.tf2outpost.com/trade/8600652 - 4 days

http://www.tf2outpost.com/trade/8542654 - 6 days

http://www.tf2outpost.com/trade/8578447 - 5 days

http://www.tf2outpost.com/trade/8571832 - 5 days

Many trades selling it for 13 keys

http://www.tf2outpost.com/trade/8668689

http://www.tf2outpost.com/trade/8662709

http://www.tf2outpost.com/trade/8682666

http://www.tf2outpost.com/trade/8654497

http://www.tf2outpost.com/trade/8656664

http://www.tf2outpost.com/trade/8667846

http://www.tf2outpost.com/trade/8628841

http://www.tf2outpost.com/trade/8665673

http://www.tf2outpost.com/trade/8662238

Based on these, we can find that there are so many 14 keys sellers who failed to sell their huntsman, and it's easy to buy it for 13 keys. Therefore, 13 keys flat seems good.