As far as I understand, you want to use Smart VT only, this is "Option 5" in the document you referring, and in this case you can use any type SD cards for booting, but RCW should be loaded from another source, because several pins, required for Smart VT operation, are enabled by RCW, as you already mentioned.
If you want to load RCW from SD also, than please look "Option 3".
Note the document you referring is preliminary and not available publicly yet, so it is not correct to discuss it in this public community. Please create a Case to online technical support for further questions.
How I could create a Service Request?
Have a great day,
Alexander
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