I use the lense cleaning tissues (dry) and Future. Soak the tissue in Future and lay it on your part like a decal. Then paint it, clear it with a very, very slight tint of green or light brown. or keep coating with Future until it is smooth enough for you.
here is one I bought at Harbor Freight that works great for small parts and different colors in one session.
http://www.harborfreight.com/cpi/ctaf/Disp...temnumber=93506
In places where a hot towel won't work I use a Q-tip. Dip the Q-tip in water and hold it on a hot soldering iron until it starts to steam the gently press the decal into position.
I support my local hobby shop. I may pay a few extra dollars but they are there with what I need when I need it. If they don't have it they will special order it. I also enjoy leaning on the counter talking models with them, try that at a big store.
How clever of you to paint a sewer lid to look like a penny!
Seriously I looks great so far. I like the windows, I have want to try do do it but have not been brave enough to pull the trigger yet.