Well, through the course of this I did a tier VI sacrifice, giving me 15 GA souls, all 3*'s. I also have been doing nothing but LoL runs for sacrifice bait. I've been tracking everything, too, for other reasons, but I can tell you I've done:
31 tier 1 sacrifices, no rare souls
8 tier 2 sacrifices, 1 rare soul
I basically have nothing left to throw in the pit and have to hope the next two days give me many, many more souls than the last three. I'm at 170 right now and think thats where I'm going to stay, if I don't want to drop $100 on a mobile game.