Outlaw Kid, I hope I can answer your questions but I apologize that I don't yet have the capability to post pictures. At any rate:
1. making the cartridges--I use the method you described using the pin gauges, which are necessary for consistency. I found that when applying glue to the side of the paper, I had to use a glue stick lightly as my attempts at using the Duco cement for this purpose ended in the paper sticking to the pin gauge. I don't load a projectile, just a powder and lube "sack".
2. the paper--I have been using untreated curling papers, both Tru Wave and Sally brand. The Sally papers appear a little thinner and stronger, in my opinion. The difference in thickness can affect the final size--and which size pin gauge to use--if you are trying for that snug final fit in the cylinder.
3. the bottom disc--again using your method with the rice(tissue-gift wrap) paper-- I use different colors for each caliber-- I cut them out using press mounted punches from Buffalo Arms. I was fortunate to already have these as I have been loading black powder cartridges for a long time.They produce clean cut wads(rice&wax paper, milk carton)very quickly. I again use your method to attach the bottom disc using the DUCO CEMENT, which is absolutely necessary and makes this style cartridge possible.
4. the lube disc--using Gatofeo' recipe, I've tried two methods. First is a straight lube disc that I cut out using the mouth of an appropriate size brass cartridge case. They are cut from a sheet of lube. I melt the lube and pour it into a baking pan that contains about 1/4 inch of water. Just pour the melted lube right on top of the water and let it spread out evenly. When cooled and hardened I place it in the freezer for a while and it pops right out of the pan in a nice flat, even sheet. The other method(using paper discs soaked in lube), I resorted to using those heavy, blue colored "Shop Towels" as my local Wal-Mart didn't carry the brand mentioned in one of your earlier posts. More testing this year to determine a preference.
5.why straight wall case?--I agree with your assessment that a straight walled case allows for more consistent compression using weighed charges. I also agree that making the cartridges a close, snug fit to the cylinder's chamber resulted in less(next to none) unburned paper residue, even though the paper is not nitrated. Here I ran into some complications. The dimensions you gave for the .36 Navies worked great. Then I decided to make some for the .44s. I worked out a nice, 26 gr. 3F Olde Enysford load that snugly fit the cylinder of a 60 Army, and then discovered that I couldn't load it as it wouldn't clear the barrel of the assembled gun! The same size just fell into the Rogers & Spencers. I had to use a smaller diameter pin gauge for the 60 Army, and of course different lengths(and fillers) for the Dragoon and Walker. That is why I mentioned the different dimensions for different guns of the same caliber.
Why go to all this trouble? I shoot at Cowboy matches and when using percussion pistols, loading these are much easier, at least for me. A better reason is these cartridges just work great! When using my previous tapered, cone shaped cartridges, I always got some paper residue no matter what I did.The only drawback is the straight walled cartridges take a bit more deliberate, careful loading, but the end results are worth it.
In conclusion, Outlaw Kid, I have found your experiments to be instructive and useful an hope you continue posting them.