The oil bas poly is going to yellow as it ages. The darker colors shouldn't be too bad, but your lighter colors, white in particular, will definitely have a yellowish tint to them.

FWIW - I use latex for painting and water base poly as a clear coat. The water base poly does not yellow with age and is definitely good to 10% nitro. Various reports indicate it is good to 15% nitro. A big plus I have found with the waterbase poly is that IT SEEMS to be compatible with just about everything.

As Cafeenman said, be careful of compatibility, some paints won't work together or only a certain way. A prime example is that you can put enamel over lacquer, but you can not put lacquer over enamel.