i have painted several models with nail polish...i mostly use dupli-color white auto primer from pep boys or advanced auto...etc...then unless ur painting a dark color i lay down a couple of LIGHT coat of dupli-color silver lacquer since nail polish is lacquer then several light coats of nail polish u dont have to wait to long between coats...10-15 min for me...most important u have to spray closer to the model then u do with paint 5-6 inches keep it moving passed the model then sand between coats if necessary...then a couple of wet coats..
let dry i usually give it a couple days at least then hit it with clear...here is the last model i painted with nail polish...