I've never associated "dollop" with any "size", large or small. A dollop is a dollop to me, that is some indeterminate amount. The use of "dash", "pinch", "splash", etc. are much more precise, in an imprecise kind of way.

A dollop of concrete could mean anything from a bricklayer's trowelful to an entire truckload. A dollop of milk in my cornflakes has a finite upper limit (the capacity of the bowl), but the lower limit is bounded only by it needing to be greater than 0. A dollop of glue on the back of a piece of paper being glued to another is both upper and lower bounded by common sense and paper size. Beyond that, hey, the possibilities are boundless.