Thank you again
Ernie - it's Alclad Engine Manifold - there will be more to add to the exhaust, but I find this to be a nice grungy, metallic look to kick it off with..
I've made a start on the lozenge and, I know I'm repeating myself, but, wow! This stuff is awesome. I experimented on giving them a varnish before applying, but all in all I prefer using them without - yes they are delicate, but they nestle on beautifully - I've finished the undersides and haven't had any issues (yet!) with tearing. I'm just going slow and taking my time.
Started with a thin layer of plastic primer - rubbed down - then a very thin coat of Tamiya XF60 (dark yellow) which has a greenish tinge and seems a good match to the general tones of the lozenge, this is diluted with Tamiya lacquer thinner which gives a tough smooth finish - rubbed down - coat of Klear - rubbed down - which gave me this as a decal ready surface:

I gave the surface a liberal coating of Micro Set, then after the decals applied - slapped on the Micro Sol:

When dry it looks like fabric to me:

You can see here how it really hugs the surface detail:

I'll let that dry overnight and then seal it in before tackling the upper surfaces

Cheers
Guy