I just spam the lower lvl caravans if solo they are easy back 2 back and while its not 750 to 1k seals it still beats Gc leves. So a fix could be seriously increase the amount of gc leve seals or revamp them to make them reward bonuses for speed. 15mins sucks especially when mobs come so rarely. Imagine if the defend leves had new mobs coming at 30 sec intervals and reward was based on how long you defended with a mob number modifier bonus to them. That or add seal rewards to ifrit and other primal fight. 4K seals for every win in lieu of xp would rock. Problem its we need more things that reward seals instead of xp as xp can be gotten by various means anyway.