the contenders, Americana Writer (the new guy) and Scribbles (the champ)
Below you will find a photo of the test, the grid is 1/4" lines and I tried making rivets as small as possible on up to a size that seemed larger than any I would find a use for.
I dropped the card as I was working which caused the Scribbles droplets to shift
so I added a second row to give them a fair chance
To my mind there is little to choose between them at the smaller end of the spectrum, but as you get larger, the Americana Writer provides a rounder, more symmetrical rivet that is less likely to run or drip. The fact that it is white will also greatly ease the painting situation as well. I was impressed by the way it help up when the Scribbles ran.
the new champI will probably keep both paints in my arsenal, but for now, the Americana will be what I reach for first.