Man this is frustrating

"I like to tinker ..."

Good for you, sir. Damn good.

But when you tinker, especially with cables, be aware that teflon insulation begins to break down at about 250C. One of the breakdown products is hydrogen fluoride, HF, a very toxic gas.

So, when soldering cabling with teflon insulation, be a little careful - I  use a respirator and work in a fume hood. Maybe it's overkill, maybe not. Mogami bulk cabling is available without teflon, which might work better for you if you don't have the facilities in place.

Anyway, I doubt if you can improve much on simple DIY cables using quality connectors (I prefer ETI). And nothing in my system is mid-fi.

By the way, Almarg is absolutely right about low capacitance cables.

RG58U Coax. It is easy to find at electronics shops and even ebay. It has a thick solid core copper center conductor and normal (as in not foil enhanced) thick copper braid shield. It's easy to solder, unlike many other types of coax.   

I have used Rean, Deltron, and Switchcraft (especially Gold HD 3502AAU) RCA plugs.

Terry9 - good to know 

I have a friend who repairs electronics for Wal-Mart (phones, bar code scanners, etc.). Former Air Force Senior Airman in electronic warfare (AWACS). He has about 11 years of electronics / soldering experience under his belt and I'll likely have his help in putting together cabling. My soldering skills are limited to shop tools where the quality of the connection is approximately "that'll do it, she'll hold." However, I'm up for learning, and playing around with this stuff is more than half the fun of it. 

I'm using Audioquest Water RCA cables with the DBS system from tonearm to phono preamp. Would these cables still benefit from burn in on my old "Duotech cable enhancer"?

I tried many interconnects up to $400/pair and the best ones for turntable to phono stage connection are Valab solid core silver interconnects sold on eBay at around $100/pair, assuming you are using an MC cartridge.  They are superbly shielded and dead quiet, while at the same very vibrant-sounding.