There are three tools besides the reloading equipment itself which are more or less essential to the avocation. A good scale, a caliper (digital preferred), and a chronograph.
You seem to have a scale and not some device that merely goes by volume to measure powder charges, so ok on that part.
A digital caliper for taking mechanical measurements of various kinds, like bullet length, OAL of the cartridge, the mouth of the case after crimping, etc. These can be had from various places for about $25-$30.
The chronograph to be sure of the velocity of the projectile with various loads and as a way of insuring you are correctly doing everything else... as in, if your data does not agree with or is not close to "book" then something is wrong! I might recommend a CED Pro Chrony for about $100 as they are, in my experience, accurate, easy to set up, provide all the data you need, and are lightweight and easily portable.
And yes, while Clays is a good powder for very light loads that still give good ignition, it is unsuitable for anything approaching mid range velocity or above... especially for someone new to reloading! Silhouette is a very good mid range powder that can take velocities from pretty low, up into factory duplication loads and beyond without overpressure. Others in that range might include, but are not limited to WSF, Universal, Unique, and Power Pistol to name a few. For even more aggressive velocities without pushing the pressure limits of various cartridges, I have found Longshot to be quite useful as well.
The thing is to find a powder, as you have seemingly thought to do, which safely brackets the pressure and velocity range of what you have in mind for your shooting need. I congratulate you on your choices so far!
I, Procrastitron will destroy evil... eventually!
Strangely, a lot of folks who do not believe in evolutionary Darwinism seem to believe in social Darwinism... go figure!