I personally decided to skip the L-Ultimate.
Halo control on bright stars seems okayish, but on Visible Dark's video it seems like there are weird halos on small stars, which is even worse.
I'll probably go with the Antlia ALP-T Gold, or the new Askar one, which I've yet to see much about, and is super expensive.
I also skipped that L-Ultimate because of Shawn himself, he commented me that he won't rush to get it if he was in my place, and yes, i saw those weird halos on smaller off center stars, even Galactic Hunters did a test with this filter and also same result, no halo on some bright stars but surprising halo on another ones, kind of the center is ok but off center isn't, so that is not what i look for.
Antlia is nice, but it is 5nm, i really need 3nm or even narrower if possible for my B8/9, now about Askar, the results i saw are nice and amazing, but, i can't trust those, they might did a lot of processing or didn't make enough tests to confirm, and i didn't see more results recently from them, i was really very close to order L-Ultimate, good i didn't, and now i am saving for the Askar unless i see something later or very soon that it is also not good before i put that much cost.