Well, I had to give it a week to fully recover from doing that first set, I attempted L1D2 a few days ago, and nearly collapsed on my first set.
L1D2: 18:07, subbing negatives for full pullups
So, minus 12 minutes resting between sets means I completed in just over 6 minutes, which isn't too bad for me. I felt a lot better towards the end this time, I think I'm still short on the ROM for pushups, but otherwise I'd be picking myself up from the floor every rep. That said, I'm still surprised I can do more than 3 pushups in a row!
Bring on day 3 (in a week and a half probably)!