Constructing your own cables can be rewarding, fun and educational. IMO you are off to a good start by;
1. owning a lot of different brands of very sought after and very expensive cables,
2. experimenting with making your own,
3. doing a lot of reading on the subject of design,
4. dissecting some old inexpensive cable you had lying around, and
5. realizing the benefit of balanced construction, whether for balanced or single-ended cables.
I have taken apart more than a few manufactured cables and what I typically learn is that (other than those with network boxes, active dbs, etc.) cables are basically wire, insulation, geometry and connectors. Several have been quite disappointing in how uninspiring the construction was, compared to the marketing hype.
In my experience the most important attributes, in order of most important to least important, are wire gauge and geometry; wire material, metallurgy, purity, and processing; wire insulation; connectors and method used to attach the connectors; cable length; cryo and/or magnetic treatment, and cable conditioning with active signals (e.g., cable cooker). Cable routing between equipment is also important.
The main advantages of manufactured cables are the R&D that goes into choosing the final materials and geometery, and the uniformity of construction that is somewhat beyond what can be achieved by a typical DIY construction. One way I have found to remove the uniformity issue is to construct DIY cables by terminating some of the excellent bulk wire/cable available through on-line vendors. Although, I also believe a carefully constructed DIY cable, using good materials and geometry, can beat many of the manufactured cables out there.
Good luck. Keep us posted on your progress and results. Also, as Phil says, you may get more activity on a post like this over at AA cable asylum.