I have never done this using acrylic as my base, but I have done it plenty with solid wood and proofgrade plywood. Both work, but in my experience a deep fill works better with small things. Narrow fills are tough (think a flowery script). I don’t know about acrylic spray paint, but quality spray paint from the art store makes a noticeable difference to the ol’ Rustoleum from the DIY store.
Note that the paint likes to wick up under the masking, at least with wood. Have not found a good solution for that yet.