enamel and Vinyl Tracks

I tried spraying vinyl tracks with Testors dullcoat (I think its lacquer based) first and it just flaked off so I don't see the benefit.  I've used enamels straight from the bottle and it seemed OK.  Nothing will stop flaking on vinyl unless you handle them very, very gently and as little as possible.

how about this, what if they were coated with dullscoat first and then painted with the enamel?

I would use Tamiya's Fine Surface primer in the spray can.