1) The Zebralight will be more efficient due mainly to their buck drivers, versus the linear regulators in the FW3A. Here’s some examples of measurements Maukka has done:
SC64C (90 CRI XP-L2): 140 lm/W on lower output, 106 lm/W on high.
Emisar D4 (80 CRI 219C): 84 lm/W at regulated channel, ~67 lm/W on medium FET
There is, of course, a ~2x difference in price, and you trade Anduril for a different UI (although one that is still well-liked by most users).
Edit - Since Maukka now has numbers in his review, the FW3A with XP-L HI showed 93 lm/W at max 1x7135 channel, and 85 lm/W at max regulated level.
2) The default ramp ceiling for both smooth and discrete modes for the FW3A build of Anduril is the maximum regulated level.
If you want both channel boundaries, for the FW3A specifically, you can set the minimum ramp at level 1, the maximum at level 130, and 7 steps. This will result in mode 4 being the maximum 1x7135 channel, and mode 7 being the maximum 7x7135 channel.