I'm in the process of starting some custom paracord/techflex/teleios cables myself.
1. You don't really need 3:1 heatshrink, plus they are more expensive. All my 10 colours are 2:1. Most of mine are 10mm but some are more like 12mm diameter. 10mm fits perfectly over the metal type A/B connectors, metal type mini a connector and those commonly found mini A plastic connectors. 10mm doesn't fit over the plastic type micro USB but 12mm does. I'll post pictures tomorrow if you don't know which ones I'm referring to.
You also don't need adhesive, make sure the cable and sleeve is clamped tightly to the connector and you should be good. Some like to glue it down with hot glue and super glue. I've done a few cables with adhesive heatshink where I put half on the sleeve and half on the connector clamp bit. But this adds a bit of extra thickness.
2. I'm in UK so I don't know what the shops you got out there. However, I've ordered a custom cable from a reputable UK shop, paracord from china, and paracord from a UK shop that says they are genuine. Guess which two was the most similar? The ones I ordered from china and the UK shop that says they are genuine lol. When you order just make sure its the 4mm type III ones with the 7 inner strands inside.
3. I have a reel of these:
http://cpc.farnell.com/pro-power/8723eq-100m/cable-twin-twisted-pair-8723-eq/dp/CB15204http://uk.farnell.com/pro-power/htc3024-1/cable-alarm-screen-4-core-100m/dp/1643740One is shielded and one is unshielded, with a bit of price difference. The unshielded is more flexible than the shielded one I have but some shielded wire are still quite flexible but this may be due to the higher awg or thinner sheath. You also need to fine out the sheath diameter (overall outer diameter). Mine are about 3.5mm and paracord cord fits over that nicely. For most keyboards, 28awg and unshielded are fine since they don't draw too much power (you can read up things like voltage drop to awg size).
I wouldn't even bother taking out the 4 cores of a wire to remove the shielding, then put the 4 cores back in. It's very time consuming and not worth the effort, just buy unshielded wire if you don't need the shielding.
I plan on posting some photos of what I've been up to with my cables but I haven't got all the stuff I need yet, still waiting for more connectors. But I made a instagram for my cables (shameless plug
) if you want to check out mine
https://www.instagram.com/skdcables/
