Re paper patching
Hello Hawk...what mold and cal are you trying? As I lived in Manitoba I can relate to waiting for warmer temp! You might find it will help to thin your lube if using in colder temps, as paper patches seem sensitive to that. I use mineral oil of about 5% volumn added to the wax/vaseline melt mix. Please post as to how it works for you.
Hello Ribbonstone...as Hawk indicated above, I believe a slightly larger diameter is usually more accurate, with upset being minimal. You can also if possible use a thicker paper for patching. As long as the cartridge can still be freely chambered. Also there is more blow by if bullet is initially quite undersized. I haven't used mini in a cartridge, but for less fouling you might consider H777 in your 50-70. I have always filled base of minis level with lube, also possibly use thin card wad to seperate grease cookie from base of mini. Then grease cookie should not be pushed up into hollow base. Likewise post your results to let us know how it works out.
Happy hunting and shooting.