I have painted my kayaks with Rustoleum (Tremclad in Canada). This paint has always served me well. You can buy it in pints - one will serve easily for two coats. Generally, one coat has been sufficient. I don't know anything about Interlux but I would imagine that if you can find a pint size, that will suffice. Depending on how you use the kayak, you can always keep the remainder of a quart for touching up scrapes. Bear in mind that these paints need a full month to cure properly. You can use the kayak after a few days of drying without the risk of damaging the paint if you use it gently during the first month.

Robert N Pruden