Capt Kidd looks like it's even harder to do! I reckon anything with big arcs or part/s of circles is hard. I did my circles by using a can of coconut milk from the cupboard. It had the correct circumference (51-52mm) and I used it unopened. This meant that the can was strong enough to cut the circumference with a pencil craft knife. I then use 400 grit paper to smooth off any inconsistency in the circle shape that I cut out. Then I cut each circle shape out so it's square on the edges and then I can position the circle part so that it's the same distance (top & bottom) and (left and right) from the border/s of the "Square" that it sits in. ....Probably not the best explanation but I'm sure you get the idea. To check: I run the tape measure from the front to the back of cab and see that all the circles are in a 'straight line' from the front to the back. I found that if you measure and place each circle carefully, then all circles should wind up in a 'straight' line. When I measured this box (especially the blue squares I found that all squares were not exactly the same size. Most were 88mm but every 4th square turned out a little bigger (89 or 90 mm). I put this down to factory error and tried to correct this as I did my vertical lines for the blue. I also used fairly thin cardboard so that I could cut reasonably 'cleanly' and without breaking my hand. I then stuck the circle cutouts down with masking tape at top, bottom, left and right. When all circles are down I then masked out all other bits of the box. Now when I go to spray, there should only be the circles themselves that are exposed and ready for the paint. .......No painting today though .... just too wet for good drying.