1.)If I follow the instruction exactly as they are given in the Lee Kit, use the proper bullet weight and type, the small pistol primers, the powder given for said bullet type and weight, and the prescribed dipper what are the chances I’ll blow my hand off when I cycle this stuff through my Gp100?
Not too much of a chance, many have used this setup without a problem. I have always weighed my loads of powder, never used the dippers myself. Do they tell you what powder to use? The dippers dispense base on volume and the volume of powder will vary based on the type of powder. Some are fast powder, some slow and some should not be used for pistols.
I would still be more comfortable if you could weight the amount of powder that comes out of the dipper before using it. A small electronic scale is not that expensive and would be a good addition to your equipement.