Wire, materials, geometry and connectors are four things DIY cables have in common with manufactured cables. After making cables for my own use for the past 15 years, and comparing with pretty good and somewhat expensive manufactured cables, I believe you can do well wrt SQ by building your own but.....probably not on your first or second attempt. You can get close to the sound of some high priced offerings by using the high quality, bulk cables available and terminating them with first rate connectors - a good bang for the buck option but not inexpensive.
I find the Cardas solder easy to work with. A Hakko soldering station helps too.
I agree with you on both counts and would add that a hydraulic crimper is also a good tool to have for SCs.