Painting trim on an auto

Either or. Whatever gives you the best results. People do it both ways. Strips take a steady hand and a good eye to make sure they are lined up properly. If you have some spare parts to practice on I would recommend doing that until you get the results you want before working on your main model. Try both ways and see which works out better.

If it is chrome trim you are painting, have you tried Bare Metal Foil?  They make a chrome version that beats any paint by far.  Most of us cut a strip larger than the strip of chrome, then cut through it like you are talking about for masking- same idea.  

It takes a bit of practice, but not that much.  And it results in a great appearance.  They also make a black chrome version for black areas.

+1

I totally agree with above poster. I've used bare metal foil numerous times on my car kits. Makes th ekit look more realistic than painting the trims. Very easy to use. They come in silver chrome, gold chrome, and black chrome.

I have the silver BMF, but I need to paint it in black, I have a bottle of black chrome trim but I think ill order the black BMF, I don't want to mess up this paint job, it's the best one iv done yet lol Thanks guys!