when I said "I believe what he says is correct" I was refering to what kamal farid said
i.e. its better to use ⲡⲥⲛⲁⲩ but using ⲥⲛⲁⲩ alone is also ok
accroding to Fr. Sehnouda u can use ⲥⲛⲁⲩ as in
ⲥⲙⲟⲩ ⲉⲣⲟⲥ ⲙⲫⲣⲏϯ ⲉⲧⲁⲕⲥⲙⲟⲩ ⲉⲡⲓϯⲟⲩ ⲛⲱⲓⲕ ⲛⲉⲙ ⲡⲓⲧⲉⲃⲧ ⲥⲛⲁⲩ
this line is part of prayer wrote by Fr. Shenouda
but if Fr. Shednoua of Kamal farid said that this structure is correct does it mean its correct?
No, u need to review original coptic text
so am I sure? no, I am not
the example you quoted from Fr. Shnoda
is about something else
صيغة المثنى القبطية
that is when refering to two of anything
you just add cnau at end of them and keeping
definite article "pi"
but we disccuss on a defernt issue
also,i agree with you that we should not rely on coptic teachers rather than a text that do exist
but from my point of view his opinion should be respected
as being a coptic teacher for many decade
so forget about Ph.D...
you may kenw why he had not that dgree yet