First of all, I was quoting from the original post by so right, so your questions should be addressed to him. Nonetheless, I will try to answer you as he might:
“1) You have not given an operative definition of the word Ruach Hakodesh. Please tell us exactly how to tell the difference between a sefer that was written bRuach Hakodesh, and one that wasn’t.”
I am not sure that is possible. After all, its not like its going to say it in the inside of the cover.
“2) Your statement “they get a certain level of siyata dishmaya” does not help very much. How can we tell what level they received?”
I believe so right said something to the effect of any Godol has Ruach Hakodesh. So it would appear that one can tell if Ruach Hakodesh is in play or not by looking at the author, but necessarily by looking at the actual text.
“2A) Did Isaac Newton get Siyata Dishmaya when he wrote down the 3 laws of motion, or was it a case of kochi v’otzem yadi. Assuming it was the former, are you saying he had Ruach Hakodesh?”
Well, technically speaking anybody who does anything has Siyata Di’Shimaya, and I’m not sure exactly where one would draw the line… looks like we’ll have to wait till so right wakes up for this one.
“3) I assume from your other statements that writing Bruach Hakodesh does not literally mean G-d told him every word, as you say it can even be wrong but still be Ruach Hakodesh.”
Yes, that would appear to be the case.