Couple of weeks ago, I needed this template to help with painting ten (10) 123 wheel covers. Having no luck with the search, I decided to mask the appropriate areas with tape. I taped a very sharp-pointed blade to one side of navigation dividers (basically child's drawing compass without the pencil) and using the center of the star for overall center, was able to cut the masking tape very nicely and efficienctly along the appropriate curved lines; removed excess tape, leaving the appropriate areas covered.
Edges cut with the sharp blade are nice and crisp.
Eight of the wheel covers I painted had MB original paint of wrong color, three were right color but very faded and worn; two had no paint.
Areas to be painted were wet-sanded with 600 & 1500 grit paper & wiped down with a liguid sanding aid (deglosser) just before painting. MB # 623 (ivory) paint was applied via spray can purchased from Tower Paint @ $20/can - well worth it for me. I tried to not let paint build up too thick on the surfaces, but I did make it a little thicker than MB original - paint on most of the originals appeared too thin. I carefully removed the masking tape soon after painting to allow the edges to "feather-out" very slightly, so they would not have that "masking tape look". Finished products are nice and smooth and glossy - almost as good as original - in some ways better than original. I also painted couple of areas on the car - upper right rear quarter panel & entire left rear quarter. 'Hard for anybody else to tell that I've painted those areas - match is beautiful!
According Tower Paint, they can mix any color, etc., using paint chip or the manufacurer's paint code. Check towerpaint.com.