Reasonable RCA Connectors?

Hi guys,
Can you explain what is the difference between model of KLEI? :
Copper Harmony,
Silver Harmony,
Pure Harmony

What is a difference in sound?

I have Xhadow RCA connectors, Switchcraft RCA connectors and Duelund 16ga tinned copper cable.
So I did fast comparison between  Xhadow and  Switchcraft RCA  connectors.
Xhadow has more extended, detailed and smooth high frequencies. 
Xhadow has more bass. IMHO the mid-bass is a little bit bloated.
 The mid-range sound dissembled, because  Xhadow emphases high and low frequencies.
Switchcraft RCA connectors sound not as clean, the bass a little bit lightweight. But mid-range has much more rich tone, more dilates and sound in general more natural and musical.
Despite a huge price difference I prefer sound of  Switchcraft  RCA  connectors over  Xhadow. Yes  Switchcraft RCA  connectors are not perfect but in my test they sound "tuned" more right compared to  Xhadow.

Which KLEI model do you recommend for start? 

How many hours break in time for Pure Harmony?

I never seen such compatibility issue between RCA connectors before!

Yesterday I soldered KLEI Pure Harmony RCA connectors to my DIY Duelund DCA16GA cable.
When I connected these RCA to my Chord Qutest DAC, I damaged Qutest female RCA connector central pin contact.
After that, I opened Qutest and see contact plate was moved from its place.
I returned contact plate to it’s place.
Now my Qutest works again! But I can’t use KLEI RCA connectors with it.
On other hand I can use cable with KLEI RCA connectors between my phonostage and amplifier. Both use Vampire female RCA connectors.

This review is my IMHO.
I compared two similar Duelund tinned stranded copper twisted pair of 16 gauge.
One was with KLEI Pure Harmony RCA other with Switchcraft RCA.
KLEI sound much cleaner. The focus of instrument is pinpoint.
Instrument separation is great. The sound is super smooth. Tonal balance is on the warm side of natural. Compared to Switchcraft, midrange is lusher.
Swichcraft sound dirty, soundstage is big but instruments focus and separation are not such great. But Swichcraft wins in dynamic, speed and more real tone of brass instruments. Swichcraft sound is more open, KLEI is fuller and darker.
KLEI serves music in contemplative way. It good for baroque music for east cost cool jazz.
Switchcraft shows more emotional side of music.

My KLEI did only around 24 hours, but with FryBaby2 that is much more intensive compared to normal listening break in. 
I will try to do this comparison again after a long time of using KLEI.
I also want to compare KLEI to Furutech FP126G.

Furutech FP126G are very well made and sounding RCA connectors and are not expensive at all.