Modded high-tops!

[Kinetikat]

OK, put clear gloss nail varnish on one panel of the design last night, and left it to dry. Just checked it, and it looks as if it won't need the matte top-coat - it's settled into a really nice satiny finish.
Should keep the pen work looking nice, and also should be easy to touch up or refinish if needed.

[James Hood]

Exceptionally clever.

Another possibility for an overcoat might be either acrylic spray varnish or artists' spray fixative. Mask off parts not wished to be sprayed with low-tack blue tape.