There are numerous loads for the 45-70 using Unique and similar powders. We should note that when Unique was invented in the late 1890s, it was as a "gallery" or reduced load powder for rifles and lead bullets.
Here are a couple of interesting places to look.
www.guns.connect.fi/gow/arcane1.html
www.guns.connect.fi/gow/arcane2.html
www.guns.connect.fi/gow/arcane3.html
www.gmdr.com/lever/pistolpowi.htm
This is all very interesting reading.
I have tried a number of these loads, and they work pretty well. They are VERY quiet, and since the bullet is so slow, they offer no recoil either.
I have never been in favor of using fillers like kapok in cases, so there is only a little powder in a large case as mentioned. Yes, double or more charges are a possibility, so great care is required, but then isn't it always? Especially when you first try any of these loads, it is the wise man who will look down the bore to be absolutely sure that the bullet has in fact cleared before firing the next.
Enjoy, and be careful out there.