If you're going to bother commenting on a big long email, please
_CHOP OUT_ content which is not relevant to your reply.  I paged down 5
pages, hit end, paged up, found no comment from you, so I'm not going to
bother reading anything further in this message.

Help your readers to read your email.  Don't expect them to search a
1600-line email message for a one line reply.

(This has been said many times over the history of the Internet.  There's
etiquette documents on Internet mail stating it too.  Please, comply
with it or you will find people will ignore your messages.)