Hi cinqster
Since you didn't get my PM ( i do remember now that you mentioned again having trouble with those ) here's my message again...well part of it.
Back then i suggested automotive polyester body filler ( the stuff you get at auto stores or supermarkets that's white with red hardener making pink putty...) over yellow Urethane foam for shaping the body. The stuff sticks to pretty much anything ( i use it on styrene, resin, metal or whatever else i build with ) and you can sand it to a smooth surface.
Well it looks like you got beyond that point by now:-) Very nice!
Secondly in post 45 you asked about a "cling film" to check the surface of your model. If i understand that right the answer to what you're looking for is "DYNOC". That's a thin painted film used in clay modeling to check surfaces. It usually comes in silver ( perfect for your Porsche :-) but also black, red and other colours. You drop it in warm water, take it of the carrier paper and then stick it on your model. It's not a decal though. It's flexible without Microsol and you can peel it off and re-use it a couple of times.
The bad part is, that it's hard to get ( normally not in small quantities ) and not exactly cheap either...
The cheaper alternative for you would be to use household tin foil that you can get to stick on your surface usually with a bit of water ( and it should follow the soft surfaces of the RS60 quite nicely ) or the transparent foil you use to cover and preserve food ( a bit of water sprayed on the surface helps again...at least it does on clay ).
All these help to read the highlights on your model a bit better than the matt surface you have right now.
Anyway progress looks great on a serious challenge you chose! I'm impressed and wait for more :-)