Run REW prior to treating room

REW requires some learning and practice to take good measurements and can be a deep rabbit hole in interpreting results. Then there is the challenge of designing an implementation.  I hired Nyal of Acoustic Frontiers and highly recommend him to help bridge that gap. He has access to acoustic panel products and implementation that retail customers do not. While some panels and speakers placement affect both a room is divided by the Schroder frequency. Below the frequency the become modal which requires a different approach than the ray-like sound dispersion in the higher frequencies.  

@grunge1000 ​​@pindac 
Congrats on considering your room as it plays a huge part of overall sound quality, but can be a lengthy learning process, so buckle up! ha ha

A couple of points to consider:
(1) Room Treatment Sequency
I have found that the following sequence is best when treating a room so as not to have to chase your tail and re-do measurements endlessly:  In general, strive for Left / Right symmetry and know in advance that asymmetrically shaped rooms (or walls made from different construction materials)  most often need asymmetrical treatments to achieve acoustical symmetry.
(i) Early Reflections - focus on the first 0-10ms which is critical for imaging (and helps with tonal balance) and measure in 1 octave intervals with center frequencies at 500 / 1 / 2kHz, or for more fun use 1/3rd octave intervals.  What is the difference in dB between L and R reflection peaks?  Are the peaks louder than a frequency band dependent threshold? How long do the peak asymmetries last in milliseconds?  If the L/R difference is large enough and L and R are louder than the threshold and persist long enough, then it needs to be treated - absorbed, diffused, or redirected via reflection.
(ii) Bass Decay Time - use a T30 metric and measure in 1/3rd octave intervals.  The mids/highs should be a fairly flat consistent decay time and rising in the low bass to about 150% of the average midrange decay values.  You can get a sense of how well the bass and mids blend by calculating a "Bass Decay & Warmth" metric as follows:  = [ T30(125Hz) + T30(250Hz) ] / [ T30(500Hz) + T30(1kHz) ] which should be between 1.1 - 1.4.  The hertz reference in the equation refers to the center frequency of a 1/3rd octave interval.
(iii) Mids/Highs Decay Time - avoid over absorption of high frequencies to prevent a dead sounding room; use reflection and diffusion to maintain the high’s energy and decay times
(iv) Frequency Response - use modest DSP/EQ in the bass region

(2) Where Measurements CAN/CAN NOT Help
REW (or OmniMic which I prefer to use) can produce a lot of charts based on settings across many different chart types.  They act as islands of information without bridges that connect them.  I’ve created an analysis layer that sits atop of the raw early reflections/decay times/frequency response data that creates a "Severity Score" that considers L vs R (relative) symmetry and also L/R vs target curves (absolute).  These scores are then weighted based on human perceptual sensitivities and thresholds (thanks to psychoacoustic research by Toole etc.), then normalized as a score between 0 -->1 (0=good, 1=bad) so you can compare areas that need improvement across the 3 pillars of early reflections, decay times, frequency response.  This allows prioritization based on max severity scores which I typically use with (1) above in terms of room treatment sequence.  Moreover, charts can "overstate" a problem that may have a low likelihood of perception, and "understate" where perception would easily detect the asymmetry.  It can be a deep rabbit hole . . . ha ha

At the risk of shameless self promotion, the last two PMA Magazine articles I wrote under the name ’Kevin Fielding’ addresses the above issues in case you’re interested.
 

Thanks @kevinzoe --Good information. 

I have the intention to use learn from all that is made available on this area of interest. The available Free Software and Tools that have been suggested to me, will also be utilised to attain an education for myself and see what I am able to achieve using the software and devices.

Anything to be undertaken will only be done when the required action is confirmed by an individual who is very familiar with this type of activity, I am also able to share produced data with a Professional who advises Speaker Producers on their needs following data analysis.

It is a waiting game until requires support is readily available to assist with my needs and enable me to compare my findings and interpretation for the Room / Speakers to theirs.      

Worth using the AM acoustcs room mode simulator for help including speaker and listening placement