<<< Gary, How well does external inductive coupling to the internal ferrite
work with the CC-Skywave or similarly inaccessible radios? >>>
The stock Skywave and other internally-crammed Ultralights work great when inductively coupled to an FSL antenna or air core box loops. In fact the final boosted signal with a 5" or larger FSL antenna is exactly the same whether a stock or "Supercharged" Ultralight is used for DX station reception.
There have been several times when a high "Supercharged" radio casualty rate at the wacky Oregon cliff site made it necessary for me to pull out a stock Ultralight to use with the monster FSL's, and the resulting MP3's sound exactly the same. The advantage of the "Supercharged" models is that they give you an early warning system of great DX signals coming in, while the stock models stay relatively quiet unless they get an FSL antenna boost.