Assuming you're in the US, go to redco.com. They've got the best deal on the Mogami, and you can get the 1/4" connector there. I got a Neutrik NP3X. I'm assuming you've got the spare HiFiMAN SMC connectors, but if not you can get them from Head-Direct, or Double Helix Cables sells a different design that's supposedly easier to work with. I made two cables using HFM connectors and had no problems.
Guessing on the prices, but close to...
- Mogami @ $0.64/foot
- Neutrik $4 and change
- SMC connectors $12ish
- Paracord Planet paracord from Amazon was $5 for 25 feet, free shipping; $4 for 10 feet, so worth getting extra
- Heat shrink... already had it ;-)
- A ballpoint pen hacked to produce a cylinder that will conceal the Y split; Papermate Eagle worked nicely
As for the time it will take, that depends on your skill level (again, mine was pure noob) and how neat you want to be. I produced a ridiculously detailed guide for another Head-Fier. PM me if you want the link. It's written for us noobs. Took me a few hours, with smoke breaks, etc. I've got a quite expensive aftermarket cable and I can't tell the difference between it and mine. And my cable is.... well, mine Pride of work and all that.
It was a good excuse to buy a few other things, like a soldering station (nice one for $55 from Amazon; $150 retail, or so it said), wire strippers, a few other bits a pieces. Made a nice white cable with black connectors for my white Q701s All three are wonderfully light, though I do need to redo the first one to get rid of the sheath and copper shield from the Mogami. Too stiff compared to the other two.
D: :D See what I did there? ;D