Big fishing is fun and actually not that time consuming...depending on your luck, of course. It's better to wait for ShB now because of gear melds needed (the higher your gathering the better) but if you were to use this website and just go after fish that are in window while you have downtime, you could probably knock most of them out easily. I dragged my feet all expansion on fishing and finally decided about a month ago to start fishing them - I did all but 15-20 of the SB fish in like 2 days. It's less time consuming than you think. Food, FC buffs and especially cordials help a lot too.