Can anybody offer some advice?

I want to buy Elzevir - expensive but so good! I am not sure whether to buy the Book or Regular - can't buy both. The bookis slightly heavier, and apparently more akin to how regular would have looked during the days of foundry type.

The pdf shows both variants, both look excellent, and I just cannot make up my mind.

my use for it is for body text, letters, documents etc

Anyone have any thoughts!