I quit reading those books and articles, the bolt closes, the chamber gets dark, after that they claim no one knows where there are when finishing a chamber, so check often, ream a little, check a little.
Hand finish? The reamer will need to be turned with something, I have extensions and 'T' handles, hand tools, cutting oil must be used, reaming does not require effort, with the barrel supported on it's end, the weight of the reamer and T handles is all that is required, I would suggest getting a depth micrometer or dial caliper.
No mysteries to chambering and there is no excuse for not knowing how short a chamber is, you are going to shoot ammo, not gages, use a full length sized case (no powder, primer, bullet), install the bolt, rotate and seat the lugs then pull the bolt back, measure from a flat on the receiver to a flat on the bolt, recording reading, repeat this procedure with the full length size case, the difference between the two measurements will tell you the amount of metal to be removed before the bolt will close. .005 is the difference between a full length sized case and a go-gage, therefore a go-gage can be used to determine how short the chamber is in thousands, it is not in the book. And, when finished, the lateral travel of the bolt (back and forth) will indicate head space, no travel, no head space, a lot of travel, a lot of head space (on some rifles), in the perfect world with the perfect chamber and a go-gage chambered, the bolt will have .000 lateral movement, with the perfect cartridge the bolt will have .005 lateral travel.
I am not that far from you, if I can help let me know. I am not sure what you had in mind when you said you could remove metal etc., removing metal from the face of the barrel will increase case head protrusion, on a Mauser case head protrusion is .110, if for some reason you face off the barrel, move the shoulder at the end of the threads forward the same amount..
F. Guffey