I found 2 roller pads of different density(cheap yellow & thicker/better black - shurline brand) but I only remember 1 foam brush(dark gray/black).

I bought a quart tupperware thing for mixing & storing.It sealed airtight but still might need to add a LITTLE thinner when you reopen it. My thinking was by mixing larger batches & adding more before it was all gone I was more likely to have a consistent thinness & therefor consistent color shade.

If you're repainting soon you can reuse the brushes but they're cheap so just buy several.
underside of raingutter - either brush on or use a stock color so you can spray. I sprayed my doorjambs & hood edges, worked great. Did them after 2 rollon coats on the surface then wetsand to eliminate any transition change.