Past simple + Past Perfect Progressive

Hi.
I had thought about one sentence and tried to find answer in google... so i'm here. )))

Guys, could i say: I forgot, how amazing it had been being(for example, if i talking about feelings in the past during some action, which ended in the past(party, eating unusual food)?
First - it was amazing, than - i forgot it ))))

And 2nd question: How i could say same sentence, but, when i talking about my feelings, for example, when i was reading the book.
I forgot, how amazing that book... ?Had been? ?is?
----
I red the book, which i had red many years before. I forgot how nice it had been. ????


Thank you for your help! )))

(Not a Teacher)

"I forgot how amazing it had been being."

I don't think you'll ever see 'being' used with the past perfect. 'Had been' already has a 'be' verb in it.

I thought i have to use past progressive, because i want to talk about process(action) in the past... not about result of that action. :-?