Pentel
I did use one of the step drills that I purchased from a vendor here on IAP. He told me at the time it was his last one is stock. Before that though I came up with my own method for using 2 drill bits with good results. I only bought the step drill because it was easier.
I sanded these with 220 dry to smooth the basic shape then started sanding wet with 320 and continued to 2000.