Well, I ran many matches Maia_1800 "default setting" vs Maia_1800 "extreme width search"; no way to get the latest win a decent share of the games, even granting it a massive acceleration (I tested up to 16 times the nps limit). Worst: even if accelerated enough to reach same or so and even deeper search depth, it keeps being unable to cope with the default setting.

I then tried out some intermediate, more reasonnable settings, but the "brute force" effect (ability to detect the mate in 1 threat at low search depth) just vanished.
In a nutshell, I could not get a really convincing behavior and shall stick to the default setting for now.
Cheers,
Eric