We sprayed the Mortein Barrier outdoor spray on ours, if you hold it back so it does not leave a huge amount of residue on the tent your proofing should be fine, if your really worried go and get some ant sand and find the nest.
Do you know what kind of ants they are?
Sugar ants shouldnt eat the canvas unless your proofing has some kind of sugar in it, some ants just burrow through anything soft as its in their nature to do so, bit of bug spray usually keeps them away.
At home we had a nest in our tent pulled it out before a trip and there were ants everywhere, thats when i hit the edges where contact between trailer and tent meet with the mortein havent had an ant since, plenty around the outside of the camper but nothing inside or on the tent now.
Good luck hope they dont make too much damage.