I didn't notice any more drive. But you're right, transistor swapping may get you there. What happens if you leave the diodes out?
I tried a TL072 and a NE5532 IC in the bluesbreaker but didn't hear much difference between the two. The discrete op-amp had a less crunchy and smoother distortion and a fuller sound - maybe from harmonics? I'm playing acoustic Gibson's with active fishman pickups so there's tons of gain going in already. I needed a subtle fuzz. But the strat sounds good through it too.
I sent it off to friend who's a much better player, I want to see what she thinks.
Meanwhile, I've got to try the vulcan.