Nemrod,
It seems that the Inon H100-28 LD is the best lens available at the moment, better than the Fix UWL - 04, Inon UFL 165 fish-eye, Dyron fish-eye, etc. and the lens to go for? If I remember correctly, you said you prefer the Inon WAL 100, and the Inon H100-28 LD is the upgraded version of it?
Until somebody does something similar to what I did earlier thsi year and last, Great Summer Wet Lens Shootout, etc then the answer to your question is unknown. I, unfortunately, due in part to a circumstance with my leg, will not be purchasing said lens for testing but if somebody want to loan me one I could try.
At this time I know of no way to mount the Inon LD lens to the FIX or Recsea housings. I would go with the UWL-04 or Inon UFL165AD because they are half the price of the Inon LD or 28AD or 67mm offerings when one includes the price of the dome kit.
N