How to select a good Speaker Cable

Mr. vinylshadow

The relation of a copper conductor (cable, wire) is:
R = ro x L (m) / S (sq. mm)
When R is the resistance (in Ohms),
ro is the copper constant conductivity value,
L is the length in meters and
S is the cross section in square millimeters. 
You may use the AWG
table: https://www.powerstream.com/Wire_Size.htm
For every 1/2 on length, that the cables is shorter, you can let also 1/2 on cross section, so the R will remain the same.
Why 2 meters?
Why not 1 m? (3') it's more than enough.
On 1 m you can go with #12 AWG.
For 2m as you ask for (!) is #9-10 AWG.
A DF of 100 is not much for monoblocks. A mediocre Japanese receiver of the 70's was 40! 
Follow my recommendations about eBay and Nakamichi banana plugs, you will end under $100.- for the best results.
The Nakamichi banana plugs can have up to an #8 AWG cable, without problems. The labor time is about 1hr. the results: excellent.

Mr. Dave_b2
MIT use a small box along the cable. that has some passive components.
Look at it is some filter, if not a gimmick to charge you and doe nothing!
I opened once an MIT cable, they use HF antenna cables, with shield and solid middle wire. They are shorten at the ends.

Look at a cable that works with your DF and length. Pass me the information and I'll calculate for you the AWG. It's for free.
At least you will know what AWG you need. The brand providing it is insignificunt.

Mr. tweak_1

The Wire World website information is irrelevant. 
Use an OFC cable that is flexible enough, with lots of thin strands, would be the best. For length: you need to say. The thickness for such length, is set by the Amp's DF spec.
All tricks as for skin effect, cable's geometry, cryo treatment, Bi-Wire, or any other of that long list (including Burn Ib (BI) are nothing but BS.
My suggestion, to use two separate (the red and black), and not a twin in one cable. That is the best for no Capacitance. 

Mr. b4icu-
From what I’ve read about damping factor, a high number is not a be all and end all. A lot depends on the speakers being driven(JM Lab Mezzo Utopia’s @ 4ohm, 92.5dB sensitivity) and the marriage between the 2.

Not to sound defensive but I have a feeling that Jeff Rowland knows what he’s doing with his amp designs.

Your equation does not take into account the speakers and their resistance etc..
The Model 12 manual lists the DF value as >(greater than)100. Not 100. So, I don’t know how much greater than 100.
The president of PS Audio states that a DF of about 100 is going to control a speaker just fine.
https://www.youtube.com/watch?v=qFifYcepPaM
Anyhow, the system sounds great but better speaker cables will be even better.... Vertere Acoustics mains and speaker cables all start at 2 meters. They did tests and that is the minimum length they were satisfied with. I asked about 1 meter mains. No go...I cannot go 1 meter anyhow but I will certainly keep the cable gauge in mind.

Thank you.

Mr. vinylshadow

The DF is a given, once you purchase your Amp. You can look for a better, or let it be as is.
DF is defined as the ratio (pure number) between the constant, pure resistive value of 8 ohms of a speaker load, divided by the Amp’s output resistance.
The figure of output resistance is the way the Amp’s drives the speaker.
Keep in mind that a speaker is a complex device with reverse current, generated by the speaker to resist the Amps will to move it.
So at that part, DF is critical.
However, tube amp’s sound nice and have very low DF! less than 20...
It is nice but not right. Some like it this way, others like it that way.

Some pick a very beautiful wife and do love when their eyes are open. For the less fortunate, there is the option to close their eyes and imagine...

Some makers, often mentioned here, may have some says, but none tells you what spec. should your speaker cable have. NONE!
The only Amp maker that went this way (telling you about speaker cabling) is MBL. They mention it, but they not tell you nothing. Even the DF is top secret. Sorry, that is not a recommandation! mine is.
The idea I bring, been tested and proven. Even with over thick cables (vs calculation) that brought no sonic improvement.
It is correct that some combinations (Amp’s / Speakers / Cables) has more significant improvement, when other combination has less.
If you follow the physics and get the optimal cable as calculated, it guarantees that you are good.
Any other approach, is a blind shot in the dark. The problem is that no manufacturer is telling you which cable you need, and every try is a load on your wallet.
Yes, for those who have more money that brain, or money is not an object, it may be a game they will be willing to finance. Still a waist of time, with never know if you have reached the best or still looking...
For all others, there is a way to go, to nail it on the first and only required approach: Calculating the cable and than get one.