Hi Dave,
Being a beginner I've self taught by using YouTube and reading a few books. I started with making a bowl, I started with a 12" disc and it ended up being about a 8"er. Especially since I too started with steel and have not moved onto Aluminum yet a test piece was a good start.
It let me figure out stretch and shrink with hand tools and the finer art of plannishing which still needs some work.
This may be below your "Greenhorn " skills already but I thought it might be a starting point.
Just one suggestion.. Best of luck on the adventure...! I'll be watching for sure.
TX
Mr fixit
Chris