It's unfortunate but while modern guns hold their value relatively well, customization don't. You have to find a buyer that would have bought all the custom parts you did and then offer a good discount since they're used and niche.
Good luck with the sale, I have a Macro and love it, they're...
For those of you who haven't found a good way to carry a reload, check out reloadwrap.com if you haven't. Cheap, can be adjusted to any size, and you carry the magazine in your pocket, concealed but always indexed in the same place. Believe they have something for speed loaders as well. Added...
Met GaterBatii for a sale, was willing to meet me halfway. Prompt payment no tire kicking. Great guy wish him the best.
https://www.gulfcoastgunforum.com/members/gaterbaitii.11131/
Makes sense, I shoot one for USPSA and love it, similar setup to yours and I'm probably into it for around $1800 between milling, internals, and grips and that was me doing the gun smithing myself. Good luck, someones going to get a great gun for a great deal.
Love mine, GLWS. Are the internals stock? Seems like a different trigger shoe at least. Either way definitely a great price for a custom milled Shadow 2, especially if it comes with extended mags (at least $60 a pop between mag tube and extended base pad).