End paper thickness

[Jer]

Hello all
I am a beginner working on my first book.
I did a perfect bind with 8.5 x 11" pages, 28 lb. copy paper. My question is what to use for the end papers.
The book is about 350 pgs. so I feel like the end papers need to be quite strong for a book of this size. Would 80 lb. cover be too thick and make the book stiff to open?
Thanks in advance for any replies.
Jer

[bookbum]

60-80 lbs should be fine.

[zouhon]