Do you know the origins of the Majestic and Emperor? I now only acquire these from Australia (or East Africa for Emperors). They cost more, but the survivorship is so much better than "grade B" fish from Jakarta or Manila. Be aware that some people are reporting lower quality fish coming in now due to the supply chain growing longer because of Covid.
When you say "hypo", what is your planned limits? Big angels often come through the wholesalers and pick up Neobenedenia flukes. To treat that, you need to run hypo a specific way. Here is an excerpt from my upcoming fish disease book on that:
Barrett L. Christie, a public aquarium curator, has researched a variety of treatment methods and has struck upon one that is highly effective. The treatment is relatively simple; in a quarantine system, the fish are exposed to hyposalinity (low salinity) for 35 days. Exactly how low of a salinity is the variable that needs to be controlled. Some species of fish do not tolerate lower salinities, yet if the salinity is not reduced enough, the parasite population is only reduced, not eradicated. Barrett has hit upon a workable value of 17 parts per thousand, a bit less than half the salinity of normal seawater (this equates to a specific gravity of around 1.013). Obviously, most invertebrates cannot be present during this sort of treatment. Sharks and some rays cannot tolerate it either. Assuming the fish are healthy in all other respects, you begin this treatment by lowering the salinity to the target value over 24 to 48 hours. During the low salinity treatment, water quality must be monitored closely, especially pH. Be aware that some other diseases, notably Uronema and Amyloodinium thrive at lower salinities. Luckily, another common scourge, marine ich, Cryptocaryon irritans, is also inhibited by low salinity. After 35 days, the salinity is gradually raised back to normal. It is imperative to perform this change back to normal seawater very slowly. While marine fish tolerate a drop in salinity very well, their kidneys have more difficulty adjusting as the salinity is raised. Never return fish to normal salinity faster than 72 hours, and don’t make large changes at one time.
Jay