Speaker distance

Typically a rough equilateral triangle is best. Which every configuration gets you close to that. As @Rick_n there is some variation... 120% sounds good... 

Major variables are how far from the wall and side walls. Corners reinforce bass, few speakers perform well up against walls. Most speakers sound better with space to breathe. 

In my small room 8'h x 13.5'w x 9'd, I like the speakers set up on the long wall. Tried it both ways over the decades. 

See Jim Smith excellent book on getting the most out of your audio system - Jim setup thousands of systems over many years and makes specific process recommendations on how to get to best position in your room. Jim has sadly passed but his legacy of knowledge lives on…. Get the book

Here is a YT Video on the subject by Mr Smith. https://youtu.be/CX9y40bPkGI?si=0_BpDmadPmD6BH6-

Placing them on long wall away from the side walls is optimum IF you dont’ get cramped.  Speakers should be out from the wall and don’t sit too close to the back wall to get away from room boundry.

It’s very important to make sure your seating position is not in a null for poor bass response.