I made it to the end with only one attack die. Not on purpose; I got some bad transformations, but the deck(?) worked really well once I pruned out the second mirror die. Figured I'd commemorate this weird run.
Note: I only added that heavy block die at the last second, not sure how it would play with three block dice. Also, I was only actually playing the game for about 40 minutes—I was interrupted partway through, but the game counted the time my computer was asleep. (It was kinda slow at times, though, especially when I fought multiple tanky enemies before, especially before I enheavied the attack die.)