Not sure about Hutchinson's.
I use Tufo tubular clinchers, and they never lose much air. I set them at 180 and even 2-3 days later they are still at 160+.
Take a look at www.tufo.com the ones I buy are elite ride 23 (700x23), S3 Lite (700x21), and elite jet (700x20). They are all great, but the elite ride 23 are better if you ride in the rain or on wet/dry roads. I use the same tires in the tubular version as well, and those do not lose much pressure either. When I am a bit lazy I can even go a couple of days without checking tire pressure...