I know the title doesn't look professional... Anyway! This here is some example sheet, showing different steps/quality, and instead of doing tiers only, I plan making sketch/ink/color and a "enhanced"4th step where you have different possibilities, and can have your commission as close as you want without having to pay more for things you didnt need.
Things like transparency, lights and shadows, as well as outlines as the bg, will all be customisable the way you want, separately,

More details with my price sheet once I'm done with it.

If you wanna looks closely at the pic's details: https://www.dropbox.com/s/freqy8tms.....ef%20sheet.png