Helicopter IFR

Like fixed-wing aircraft helicopters can be fitted with an in-flight-refuelling probes to increase their range, and many helicopter types are operated with this capability. My question is how exactly is it done?

-Do they use tail booms or hose-drogue refuelling systems? Are there any risks associated with clearances from the rotor blades, especially for tail boom systems?

-What platforms are capable of helicopter refuelling operations? Helicopter or fixed-wing? The USMC uses KC-130s for this role, but many fixed-wing platforms can’t sustain the low speeds necessary for helicopter refuelling: the IL-78, for instance, has a flight speed of 440-600kph during refuelling operations(taken from the Ilyushin site), which is out of the range of any helicopter. Do the A-330 MRTT and KC-767 have similar limitations?

EDIT: Mixed up the numbers.