So what did you have to do to close up the gap in the steering wheel to column?
The gap is still there. I will probably have a machine shop cut another set of grooves for the circlips to lessen the gap. I still plan to contact RRS to get their input.

And what keeps you from pulling the wheel off as you indicated earlier?
Nothing. I can change to a Mustang column. The Mustang has a bearing retainer. I may experiment to see of the retainer can be retrofited to the falcon column.

So, what's now down low considering the "box" used to attach to the column? Inquiring minds want to know.
The old shaft is replaced by a new two piece unit. The upper is solid and the lower section is hollow. They are keyed so they won't spin. The column tube is cut at the firewall and a bearing is placed there to support the bottom section of shaft. There is still a bearing at the top so the new shaft is supported at both ends. The converted column is connected to the rack with two universal joints and a short intermediate shaft.

I'll get some photos posted later.