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.
Ernest
Last Armor Build - 1/35 Dragon M-26A1, 1/35 Emhar Mk.IV Female
Last Aircraft Builds - Hobby Boss 1/72 F4F Wildcat & FW-190A8