Placement of the amp would depend a lot on the amp.
What amp are you using/planning to use?
What volume level?
If you plan to play along with BIAB & have the lot coming through your monitor speakers you'll need to set up your interface for direct monitoring so that latency won't become a problem.
Describe, as clearly as you can, what you aim to achieve in your room.


Cheers
rayc
"What's so funny about peace, love & understanding?" - N.Lowe