Looks like it was 1,600 last time...which is weird since I feel the same difficulty issue, though last time I had a +9 slayer boost (had more money back then) whereas this time I'm using a +7 (missed the R slayer, oh well).
One thing I will note though is that last time I was attacking Rank 5's for the streak, and then moving up between Rank 3-4 and burning pudding along the way to hit the top 1000 in the leaderboards. This time around after I built up my streak to a satisfactory point I spent about day hitting Rank 2 and...after a series of consecutive losses, came to the conclusion that if I was gonna play hard, I might as well do Rank 1 and that came out pretty odd as well (Rank 2 consists of alot of trap decks, whereas Rank 1 has mostly attackers, guess players on the highest tiers don't care about defense at all, not that I'm complaining seeing as we both benefit from it).
I got all 3 girls last time and this time around, the difference being this time I literally didn't spend a dime and only burned about 4 pudding halves just to be on the safe side in terms of ranking placement. Other than that, not much difference in difficulty in the general sense, only personal due to my frustration with brute forcing Rank 2's troll defenses.
As Unreg stated, both shards events are of the same length. SEC in the terms of shard payout multiplier helps tremendously, but I think anyone highly devoted might still be able to get by without needing all of them, provided you are willing to sacrifice a bit of sleep for the cause. Thus, your perceived difficulty is probably the mix of both the higher slayer multiplier and the lower cost of both girls.