Ray Tracing

[Towlie03]

Hey Guys your input is appreciated.
I have a 35'x25' (9'7" ceiling) detached garage. Neighbors are not an issue. The external walls are 2x4 with drywall and insulation, the ceiling is double dry wall with a roof cavity above it. The bottom 1'10" is cinder block and it all sits on a cement slab.

Now before I get crazy into detail my first goal was to design a control room. I used the ratio 1:1.4:1.9 (9'7":10'11":18'2"). My listening position is set to 6'11",I plan to soffit mount my Neumann 310s.

Attached is my first attempt. I am brand new to Sketchup, everything is to scale, but I am only really designing the interior wall right now for the angles and size.

My question being:
1) Am I doing the ray tracing right? I did them to the second order with most the 3rds hitting the back wall which will be absorption.
2) Given the room I have should I make the control room larger?

BaseV2.jpg

Rays.jpg

[Towlie03]

Here is the updated plan. Think it uses the space better.
Thick walls at the front are double studded, back one is single, to isolate it from exterior wall.

update.jpg

[Towlie03]

I have found where and what angle I want to slant my ceiling at, question is, do I make this angled ceiling dry wall, or do I float a cloud with the hard back of it being the angle and height the ceiling would have been?