The Starr cartridge is linen, not paper, but for the Starr carbine you could easily use a Sharps cartridge.
The "Gwyn and Campbell" is confusing because depending on who was referencing it (currently or back during the Civil War) Gwyn & Campbell, Union, and Cosmopolitan were all used to refer to the same gun.
The proper bullet (definately not MM#656) is the TT#88 (MM#12 if you insist on using a reference current in 1975) which also utilized a lined case (as illustrated with TT#88). My specimen measures .538 x .88 and is 380 grains.
As far as cartridge construction specifications, I will look to see is there are drawings in the Pitman Notes, Vol 1.