I have not digged into LAB yet because the default action bar is fine for my needs.
I always seperated the styling of the buttons from the general layout of the bar.
If you are using an action button
template it is quite easy to adjust the button appearance once the button is created because all elements are already there. It might be even possible to just use rButtonTemplate for it if a Blizzard action button template is used.
rButtonTemplate:StyleActionButton()
https://github.com/zorker/rothui/blo.../core.lua#L169
Doc:
https://github.com/zorker/rothui/blo...late/README.me
My config:
https://github.com/zorker/rothui/blo.../theme.lua#L39
Funny enough I was able to give all buttons in the player BuffFrame, BagSlots and for all action buttons the same config.