Thanks Paul,
I haven't found the enamels in larger quantities, and it can be expensive at the LHS level, usually around $2.50 per little jar. I have ordered a couple times from Gary at UBHobbies in Tacoma, WA (http://www.ubhobbies.com/door/) and found them to be very friendly, ship quickly, and the price is about $1.49 per jar. He was also intrigued about using them on such a buig model and he asked me to send a couple pics for him to post in his store. With shipping I bought about $40 worth of paint for the spitfire and have used about 2/3 of it. I used about $40 worth on my large Ziroli Hellcat. Certainly not the cheapest method, but i like having very little guess work with mixing (I can get the exact color then I just need to lighten it or darken it a tad for realism on the larger model), and thin it about 35-40% with acetone (I imagine lacquer thinner would work fine to...I just had a gallon of acetone there so I tested it and used it). Also, if you consider the investment of money and time in the model as it stands, then I don't think that is much to spend on paint.

And I should point out that you still need to fuel proof them...i'm sure you didn't on your electrics.