I did almost the entire light grind for my last relic via frontlines, it wasn't as fast as other methods but it was way more enjoyable and I basically got it for free because it didn't feel like a grind. The one issue with the light grind was people had to end the match with that weapon equipped, so people would refuse to swap jobs to whatever best suited the needs of the party. Making these tokens purchaseable with wolf marks solves that issue, and I don't think the issue of people queueing and leeching will be bad, especially in your case tsukasa where flames queues on aether are extremely long.