Designer – Developer Spec hand-off?

What is the easiest way to share specs with the developer? Instead of mentioning the specs in the design.

I did have a look at Zeplin, Avocode, Marvelapp etc. for handoff since we have our own library for components. Every time we need to mention the padding, text specs (font-size, color etc). In case of components, we do mention the variant size (for ex: button-xs (extra small), button-sm (small ) & so on).

But we do face problem while mentioning the padding and text specs etc. How can we save this time & effort?