That bronze color is actually part of the plating process. Objects are plated with copper, then nickel, and then chrome. Of course, when you get into super cheap stuff like these beginner tandy stamps, their plating probably cuts corners.
If you have a local contertop manufacturer, you can ask them for a sink cutout. They generally give them away, or only charge 10-15$ for a nice piece. They wont have fancy corners, but who needs that?
I carve names all the time. I use a 3/8" straight blade for bigger blockier letters, and a 1/4" angled blade for smaller or script letters. I used my 3/8" straight blades to do all my letters before buying the second knife. With practice it works just as well, I am quicker with the angled blade on curves though. I use the straight blade first on everything I can because its a lot easier to sharpen than the angled blade.
Regardless of blade type, that sucker needs to be sharp. It needs to cut through the leather effortlessly. If not, you will fight the tool and get ugly lines, IMO.