If you want to add colours next time alcohol-based markers (like knockoff of COPIC) are a good way to colour at least details. Also printing your greys on colour paper saves some extra marker paint if choosen well. For this laser printer is the best as toner doesn’t (usually) get reactivated with mild solvents.

He is infinitely cute.

Hey, if you didn’t already paint all your minis I found great video with examples how you can use both speedpaints and various types of primed bases with zenithal trick for fast gradients: https://www.youtube.com/watch?v=gT2JV3Ks41g

And here you have practical example how speedpaint works differently on different base colour: https://youtu.be/WjfHiwczl84?t=182