Question about assembling my own DIY AC Cable

The specific answer to your question is that with Furutech plugs and IECs, the connector consist of a clamp with center set screw, as shown below.  Therefore, best practice is to split the wire so that half goes into each side of the clamp.

@audphile1 made a good suggestion to coat the exposed conductors contact enhancer before clamping.  

Yarbo looks like a nice cable. Are you sure you want to use those cheap plugs on it? I’d go for something like Furutech, Neotech, Oyaide or Wattgate. 

Pure copper is a soft metal and does not have any memory retention properties. Copper contacts of the IEC will not hold the female contacts tightly against the IEC inlet male plug blades...

I disagree, all audiophile IEC's even from Furutech or Oyaide have the conductors of pure copper.

Yarbo looks like a nice cable. Are you sure you want to use those cheap plugs on it? I’d go for something like Furutech, Neotech, Oyaide or Wattgate. 
 

Wish I could afford it. I have a Gustard x26 Pro DAC which was my biggest investment so far and a lovely dyi headphone tube amp. I am using Acoustic Revive USB Cable and RCA.

Connected to my gaming computer. 

I don't even have a network streamer yet, 

Also neither Oyaide and other big brands make male plug for my country which looks like this,

I think using an adapter gives sonic detriment. But I agree some Neotech OCC female plugs would have been nice.

Do you guys think contact enhancer makes a big difference? 
I might still have some Stabilant 22A around.

I will connect it to my tube amp here is a picture of it

Pure copper is a soft metal and does not have any memory retention properties. Copper contacts of the IEC will not hold the female contacts tightly against the IEC inlet male plug blades...

The above quote is correct and is the primary reason that many AC plugs and IECs actually do not use pure copper, although some have figured out a way to use pure copper contacts in some of their products and still provide the necessary gripping tension, like this product from Furutech. This link to Oyaide indicates their use of phosphor bronze and beryllium copper contacts, which is actually common.