Dashboard cracks

Dear all, My dashboard (560SL, 1987 brazil brown)is out for fixing problem with vacuum pods, new vacuum membranes, cracked plastic heatbox, etc. I could not find new membranes and decide to risk withSLS Hamburg membranes ( they are little bit shorter than original ones). I believe they are for upper camber of defroster pod. So, the dash is out, this is the best time to fix cracks on it. I know almost all ways to to it, but would like to experiment with glued dashboard cap. I found such cap in Motorform (most probably the color will be different and I have to paint it). Do you have experience how it fit, especially around circle vents? What do you think about my idea to glue the cap upon old vinyl? Maybe you know another source with better quality caps? Best Regards, Stan