I used your method and it worked quite well. I could only find Taimiya grit as fine as 2000 and not 4000. I only used Meguires Scratch X and it turned out great! I think I will have to use a rougher grit frist next time to remove the really big dents and scratches.
here's a pic of the finished product...
'02 C32 AMG / '07 C280 / '07 CLS550 / '15 JKU Rubicon