I've been told の is formal, thus のです is grammatically right.
Yet, のだ is not. Only んだ would be correct.
Therefore, 「んだぜ、んさ、んだぞ、んぜ、んぞ」 are correct and 「のだぜ、のだぞ、のさ、のぜ、のぞ」 are not.
Do you agree? Why or why not？
As for the difference between んだぜ/んだぞ and のだぜ/のだぞ, yes, the former is far more common, but the latter form is still grammatical and occasionally heard. A fictional pompous person may well talk like ～のだぜ/のだぞ with their close friends.
んぜ/んぞ/のぜ/のぞ do not exist.
- 見たんだぜ。見たんだぞ。: OK, informal male speech
- 見たのだぜ。見たのだぞ。: Less common. pompous and/or old-fashioned
- 見たんぜ。見たんぞ。見たのぜ。見たのぞ。: ungrammatical
I don't know why, but のさ is more common than んさ, and のよ is more common than んよ. んさ/んよ sounds a bit dialectal to me.
- 見たのさ。: OK, informal male speech
- 見たのよ。: OK, informal female speech
- 見たんさ。見たんよ。: dialectal