I need some help figuring out this range for an unusual suggestion.

[Puppier]

I have this proof for a KaW Titanium Tower:

 

Solds:

http://www.tf2outpost.com/trade/18201919 - 3 buds + 5 keys (3.25)

http://www.tf2outpost.com/trade/18171257 - 3.1 (They say it was quicksell)

Buyouts below current range:

http://www.tf2outpost.com/trade/18355994 - 3.5 bud

http://www.tf2outpost.com/trade/18357824 - 4 buds

http://www.tf2outpost.com/trade/18359074 - 3.4 buds (They say they’re quickselling, but it’s on par with other prices so I thought I would include)

http://www.tf2outpost.com/trade/17906230 - 3 buds (Quicksell)

I'm having trouble deciding on a high end. I personally think it makes sense to put the range 3.1-3.5. I'm not sure though. Does anyone have any advice?

And please, don't steal my proof.

[The Radiated Banana]

Calculate overpay first. Then make ranges

[polar]

3-3.5 sounds reasonable. Took him 2 weeks to sell at 3.