Great show of Sanskrit but still got much much more left over here in the topic - :)
Can you show the rule from the books of grammars of Vedic Sanskrit or from Classical Sanskrit
that allows you to write a genitive singular for example the word in context "Sunasya Shepa" as
per your take, with a Visarga "Suna : Shepa" or even "SunasShepa".
Put the rule in response and then explain that with help of use of Shunah Shepa in a Vedic mantra,
avoid making unfounded justification.
Note : I dont follow Itrans etc while writing in english, dont expect !!
Lalit Mishra
[Unreferenced quoting deleted. -BMS]