Thanks Bill,
that's the kind of conclusions I was starting to come to myself. I have pictures of three earlier rifles (pre-1800) and they had barrels with lengths of 48-51 1/2 inches. After 1800 he seems to have settled in the 42'ish inch length, but could only find full specs on two and both were 15/16" to 7/8" tapered (with one note that eluded to a 15/16" "straight" barrel).
Also, no two locks or triggers are the same on the nine examples I found and as you note, he had some very plain stocks and the ones that are carved are not in "the same class" as say Armstrong (I hope that doesn't sound overly critical).
Before getting your response I pretty much had got down to a coin toss on the barrel selection. Figured on either a "Southern Classic" A weight in 45 cal from Rice - would give me the 15/16" breech (which I have documentation on) and is not severely swamped coming out at 13/16" at the muzzle (think it would work quite nice) weighing about 4 1/2 pounds in 45 cal, or to keep it light with a straight barrel and go with a 13/16" straight in 45 cal (maybe 40) at 4 1/2 to 5 pounds.
While I have no examples that either would have been correct (especially the 13/16" straight) I figured with the lack of information out there at least the critics wouldn't have much to point out
I kinda get the impression that Christian "scrounged" parts (locks, triggers, barrels) from wherever he could (that's what the examples seem like).
Thanks again Bill - would be interested to get your opinion on the Rice barrel - something that might be close to something he woulda/coulda/maybe used post 1800?