I was able to get the new balance rail pins (yes, the ones that were 1/4" too long) cut and set last night. After long and careful consideration, I decided to try cutting each balance rail pin using my trusty bolt cutter. Why I have a bolt cutter laying around is beyond the scope of this post, yet there it is.
Once I cut 1/4" off each pin, I was able to get them placed without a hitch.
As you may (or may not) be able to see, the .005" diameter difference is noticeable to the naked eye, yet it's a non-issue for my purposes; they are placed, they will work, 'nuff said.
Once I placed the remaining pins, I installed the papers and felts.
Easy peasy. The only step left is gluing the back rail cushion felt against the back rail pins. Mr. Miller suggests that I glue only 1/2" (it's 1 1/4" wide) of the felt at the back of the keyframe. This way, the felt on which the key ends rest and are cushioned will not harden or become fixed over time. It turns out I do not have any felt glue handy in the shop, so I'm going to pick some up tonight. Once I get it glued up, the keyframe will be officially completed. Please tell my wife that I am, in fact, capable of finishing something.