@mseaworthy: I like your custom board! Given the position of your Fn key, do you use your thumb to activate it?
Although I like Alps (and Matias) along with IBM Model F boards in my rotation, at present, most of the time I use my HHKB Pro 2, and I like the Fn to the right of the Right Shift key. However, on "standard layout" keyboards, I use the right-most key on the bottom row (usually RCtrl) as Fn. In these positions, I find it most convenient to activate Fn with the pinky.
Some would say that Topre is boring. Perhaps so, but it does provide the catastrophic collapse type of tactility that I like, yet it is subtle enough not to call undue attention to itself, enabling me to get my work done without being distracted by the keyboard.
Good luck with the sale! Someone is going to get a very handsome keyboard.