Does a drum to disc conversion increase or decrease wheel offset?

[Josh69]

I didn't realize the thickness of the disc hat was that much thicker than the drum but I see it come up now and then.

Let's assume a GM type 1-piece rotor, like a C4 or C5 unit, or even the stock style front disc set-up.

I'm trying to determine if I need to do my brakes first, or if I can order the wheels I want and run spacers with my stock drums until my budget allows for the brakes.