Kimber Illuminations D-60, proper length

Alright, who owns this one? I just bought a 1 meter run and I'm in love. Silver is the best! The harshness in the highs and mids just jumped out of my home theater and ran away! I can't wait to break this cable in a little more. Anyway, to my question, what length digital interconnect is recommended? A guy in a store was trying to tell me that .75 meters is the optimum length for a digital cable. I can't see that it would matter unless the length was really long, but then again I'm not an expert on the subject, I just spend money. Was he just trying to sell me something? He didn't sell the D-60 anyway, and I had to buy it mail order eventually.
I've heard that 1.5m is the optimum length for true 75 ohm digital cable. But hey, what do I know? I own two Illumination D-60 cables, one 0.5m and the other 1m!! Yes- they are great for the $$. Enjoy!
Sutts, have you compared the 0.5 and 1.0 meter. There are numerous sources that claim that digital cables under 1.0 meter have digital reflections that tranlate into jitter. If this is true, you should here harsher highs and poorer bass on the short cable. I do not have two cables of varying lengths to test this myself, but would be interested to know if you (or anyone else) find a difference testing different lengths.
I have two d-60's (both BNC to RCA), one 1 meter, 1 1 1/2 meter. I can't hear any difference. But maybe a hunting dog could.
I own several Illuminations D-60’s, (.5/M, 1/M and 1.5/M) after critically listening to them all on the same system with the same sample music I could not differentiate a difference. Perhaps others could.
I too have a Kimber illuminations D-60. It is a 1.5 meter RCA to RCA. I have visited the page which states optimum length being from 1.5 meters to 4 meters in the rca to rca run. In the BNC to BNC and XLR to XLR configuration he recommends 1 meter to 3.5 meters with the longer length sounding better. Personally I run my D-60 into a Dodson DA-217 MK II D. I have never noticed any effects that others claim to hear, but my speakers are the last obastacle for me to reach the true high end.