I am not sure what you mean by head space. In these rimmed cartridges that is performed by the rim of the cartridge. I don't know what your dad's notes on the right side are referring too. Maybe case diameters. But they don't seem right for that either, so let's ignore those for now.
Drop tube is for compaction. You can make one from an aluminum arrow or brass tubing from a hardware or hobby shop. You will need a funnel of course. Vibration can work too, but in a case that tall, I'd definitely go for the drop tube. 18-30" long should do.
We all use just one granulation - in your case 1f (aka 1fg) would be best,but 2f would work. But be sure it is real blackpowder not the imitation stuff.
Yup, just water, or dihydrogen oxide, or hydrogen hydroxide. H2O by any other name. but we have to make it sound technical or the guys with the black rifles will think we are all simpletons.
Depending on your bullet choice it is quite possible that your OAL could be 3.25-0.1+1.5 = 4.65" But I would stick to bullets that are under 1.4" long. How long are the bullets from your mold and what is their diameter? These are the two most important things.
East central Iowa. Not far. I'm in central central more or less. Story City. If you are over here, I could show you a few things perhaps and cut down the learning curve.