Well you can try that, but if you're not careful it might cause warping on the card.
I would try to put a plastic covering below it (like on top of a ziploc sandwich bag), before putting any sticky liquid like substance on top of it. If you put work on top of newspapers it'll just be a mess, or turn out to be some kind of paper mache.
A very similar and faster drying product I've noticed, would be a clear acrylic polymer. You could get a glossy gel medium, or an acrylic varnish. They'll have a faster drying time, since a thin coat just takes a minute or less to dry. Just brush it on with a paint brush (use a synthetic plastic bristled one, because for this kind of work, it would be better than the softer and more sensitive ones made out of hair).
There will be a tiny bit of stickiness/tackiness on it left over, since acrylic is like a liquid plastic, but then let it dry within a plastic covering, like in a sandwich bag, so it won't tack onto something else, and store it in a cool place till the tackiness is gone. Or you could try brushing a tiny bit of powder, like baby powder, to get rid of the tackiness.
I hope this helps you. I personally have only tried this for index cards and glossy printing paper, and the only problem I've noticed is that sometimes it will smear ink, but I've only tested it with pens so be careful with that. I don't think it will smear printed inks though, since you can do gel transfers with gel medium just fine. And good luck
