I use 'clean sheet' to mix small batches. Mostly use craft sticks for mixing/spreading. I cut the end square with dikes if I need a flat surface.
Spit works as good as anything when smoothing. Works good with sticky caulking too.

I have a supply of 1, 2 and 3oz graduated cups for mixing bigger batches

NRA Benefactor Member

Those who live by the sword get shot by those who don't.