PMK is claimed to benefit delicate high values, and mid-tone separation, such as encountered with fog and misty situations. I've only begun experimenting so I can't give you authoritative info. The effect is more than just contrast control.(posted 8647 days ago)If you are seriously interested in pyro, get Gordon Hutching's Book of Pyro. Virtually all chemicals we use are toxic. Treat pyro as it should be, and it's no more a hazard (perhaps less so) than: hardwood sawdust, drain cleaner, dishwasher detergent, gasoline, acetic acid, chlorine bleach, fluorescent tube phosphors... All the chemicals we use should be treated properly.
Pyro probably requires some time devoted to mastering it, and may not be worth it for you. If you are happy whith your prints now, stick with what you are doing. It's when you can't get things the way you want that you should seek alternatives.
Divided developers are a different story. They minimize the potential for mistakes. You can't overdevelop. You'd have to work hard to underdevelop. They let you mix different films in the same batch. Temperature is not too critical. They provide some compensation to allow a longer tonal scale to be captured. They offer long life, and they can be reused without compromising your results. They don't require any work to master. For an easy trial, get some Diafine, if you don't want to mix from scratch.