Well, I probably should be the least person to give advice on your pens value, I provided you with the blank for the first pen and the wings on the second pen were made also with one of my very unique woods, the Holly-Oak.
If the wood stories have any value when pricing a pen, both have one but the Holly-Oak (AKA Bay tree) wood, has the best story of the 2...!
I thought in giving justice to what makes the second pen so visualy attractive, and that is the Holly-Oak pieces you made the wings with and off-course, the significance of the Acacia species you use as the pens main body, that will be the most crucial detail for those that have religious tendencies.
The presentation of the pens should have an accompanying story leaflet/info, the combination of pens and stories in an auction of such nature, should be treated in a very different way, then taken the 2 pens to the "markets" and sell them to any passing by person...!
The whole value of the pens, will depend upon the way they are presented and the documentation that makes part of the pens. If someone will be willing to pay its true value with a high bid, will be because of these factors, they want to take home a lot more than just handmade pens.
With anything that sells cheap, comes the assumption of China made and not a great level of quality, it also gives the impression that, the maker doesn't value much his/hers work and is trying just to cover the costs to go and make another 2 pens.
An auction of this nature, should be treated as an opportunity to showcase your work, the materials you used and why such selection.
The auction price should start at a value that represents all these things I talked about therefore, the pen #1 should start at $200.00 and pen #2 at $350.00 and go from there.
I was the one to organize the auction, that would be my basis...! This is off-course my opinion as the reasons that make me reach it...!
PS: Correct me if I'm wrong but, why taxes on a donation...??? as far as I know, in Australia, donations do not attract taxes and the proceeds of a donation if used for a non-profit purpose, is not taxable...!
Cheers
George