@jo1mtb Glad to read that you are finding the AMROC tool useful. The BOLT area calculation is pretty cool. Suggest that you also run the proposed room dimensions through Bob Gold’s tool before you finalize. It is more in-depth and provides a little more complete analysis.
Re: WAF and room treatment/bass absorption, I recently read about a clever idea that might work for you: build a full-width closet at one end of the room (maybe instead of the bookcases?) with louvered bi-fold doors and fill it with acoustic batting material. Sort of a large hidden bass trap. The louvered doors would allow bass waves to enter the chamber while acting as a primitive diffusor for the highs and the interior volume would be pretty large (2’ deep X 15’ wide x 10’ tall = 300 cubic feet), providing effective low frequency absorption and would be completely out of sight and relatively inexpensive compared to standard in-room absorption products.