I think finding drill for the Whitworth's may be difficult because they were not officialy adopted by anyone. The only ones here in the U.S. were sent here by supporters "abroad". The gov. only bought 1 70lb Whitworth. The English Army bought Armstrongs. I have not seen anything in print by the CSA for they did not have that many either,though their manuals do contain some range tables.

I to would like to see the period dril also as I have one of the breech-loaders that were purchased by the U.S. Gov.

There were enough gas leak problems/ breech problems that Whtiworth droppped production of the breech-loader and returned to muzzleloaders as sole production.