Welcome aboard, EnergyAlaska!
Sounds like you are about ready to start you Grooving. Good idea on practicing, I did a few trial runs before I did one for real. Might try scrounging from shops or junkyards--damaged TB's w/ a broken corner, etc that are worthless as parts...
I'd get some type of metal epoxy for filler, JB Quick works for me, similar products discussed on the site. Be sure and get goggles for your eyes. Acetone(nail polish remover) works to clean up JBQuick before its hard so does carb. clean. I use fine sandpaper or foam sanding pads, and a small flat Ignition file to smooth down burrs/raised edge on newly cut Grooves
Also highly recommend you read through this site thouroughly--lots of info here! Click the Index button top of page check tools of the trade, Other Stuff, etc. I read a bunch before my first try.
Always ask questions here, if you take pics of your work it helps us help you!
Welcome to Gadgetmanland, EnergyAlaska!!
TracyG Gadgetman Reno