Strange Horizons will be changing its pay rates slightly to accommodate the first requirement, to "4 cents/word, with a minimum of $50/story". That won't actually change our budget much at all; a few writers will be paid a few dollars more for their short-shorts.
Unfortunately, writers who desire SFWA accreditation will now need to be careful to sell at least one longer story at pro rates -- if they sell 3 stories at $50 each, or even at $75 each, that won't be sufficient to qualify them. Be warned.