Thinking of a higher tier (Patreon)

So the idea of making another tier has been floating around in my head for awhile and I think i have an idea for how it might work.

Im sort of thinking of adding a color tier at like $25 and I thinking the images above might be the quality of the images I would be aiming for.

I also thought they could have shading using one color set to multiply but I dont know if it would add much to the drawings other then more time. Those kinds of pics could look like this

what do you all think would you be cool with just flat colors or would to want shading?