Heavy seems like it is used as "a heavy concentration of" ... and vice versa with the term light.

I agree, belM.

"Dollop" is a light-hearted word. You can like "dollop" without actually using it.

A dollop is good to see
But it's not really fare for me.

Seeing a dollop gives me more pleasure than actually dolloping it. [I'm counting calories, you see.]