Very nice !
I did one of my cars with model paint years ago too ; I just went into a model shop and picked what looked a good colour .
I didn't remove the pointers from my instruments : just slipped a piece of paper in behind to protect the dials and painted them in situ .
I'd like to obtain a combo instrument with economy gauge for my 190 as it's a late car without . Alas , the OTG's are like hen's teeth , usually expensive and often faulty , so unlikely I'll get one of those ( I do have a W126 OTG but I know it won't fit straight in , although I do have a spare 190 cluster I can look at modifying ) .
Also I still need to fix the backlight on my r129 OTG .