I surely read the forum every week!
I used a undercoat used on poly boats called Epifanes,you can use it with a roller and its filling and easy to sand.
I used 2/3 layers Epifanes and a 1K truckpaint mixed in a new Fiat 500 colour.
I experimented with several expensive rollers and ended with a normal foam roller.
Between the several layers of truckpaint i always sanded with wet 800/1200
I am still happy with the result,note that i used a mat paint which looks older
and more even.
Very important is to heat the whole tub(with a paintdryer) to avoid enclosed airblisters before you start painting,I found a whole lot and missed some which came out in the sun embarassed:
The first time I painted the wheels with a simple rattlecan in a sort off bronze
from a consstructionmarket,personally I like the old english white wheels!
As you can also read in the posts from Paul L when you are busy painting you will see every scratch and bubble,when you,re driving it everybody likes the result!
Good luck with your build and exuse my poor English