difference between な＋はず and の＋はず for nouns?

Question

I have been seeing both のはず and なはず used here and there, apparently なはず is usually used for な adj and の for nouns, but I came across this sentence recently where they are both nouns, but 1 uses な and one uses の, what is the difference between the 2? Thank you

　体調は万全のはずだし、心身ともに良好なコンディションなはずだ

Answer 1

Here, な and の are interchangeable for both instances of はず. But な tends to sound informal/colloquial between a noun and a formal noun (はず, わけ, こと, ...), so something like 彼は学生なはずだ should be avoided in very formal sentences.

Related:

• N + NO/NA/DA + わけ and generic rule?