The guys at Grace are great, I talked to them about a cabling issue when I first got my 201. Very helpful and they really know their gear.
However, while they are probably right on an esoteric technical level about the length of cabling and pristine signal path, on a practical level I don't think it matters *that much*.
Rack your 201 and directly above it rack the converter. Connect the output of the 201 to the converter with short high quality cables, just long enough to reach from the 201 to the inputs on the converter. That will probably be 6-8 inches of cabling. This is a very short signal path and should not cause any noticable loss of audio quality. It will be clean.
I'm not a fan of the idea that every preamp should come with a converter built in. In the first place, if both pre and converter are of truly high end quality, the cost will be incredible. Those portable units like the Lunatec and Mini-Me will be the low end of the price range for anything of quality. I would much rather buy the preamps and converters I want separately, on their own merits. That allows me to tailor the sound better.
You also get into a whole area when you have a one channel preamp. Some of those have converters, but only one side of the SPDIF signal is used when going to the audio interface. So what do you do if you want two channels of that converter? You'd be using up two SPDIF or AES interface inputs, or you'd need a third party converter anyway.
Finally, I used the Lucid as an example of a good low cost converter. If you are really going after a converter of equal quality to the 201, I'd suggest you think about
the UA 2192. I recently bought one and I must say it sounds great.