Depends greatly on the tires and conditions. Tubes or tubeless. fat tires or narrow. Terrain.
Old Intense DH tires didn't work worth crap at anything above 15 psi... But the Comp 16 UST tires I run feel vague at any pressure under 28 psi (which coincidentally, is Michie's recommended pressure). I used to have a set of 3" wide Gazzilodi's that felt like rocks with 10 psi...
There really is no hard-fast rule with DH tire pressures. A lot of it is personal preference and how you like your bike to feel and how you have the suspension set up. Experience plays a big role as well. An experienced (or simply skilled) rider tends to be smoother and won't flat as much.
With a tire that narrow, I would run a fairly high pressure. The one nice thig I discovered about UST tires is you can run high (for DH) pressures while still maintaining good grip and feel. Try 30 and see how it feels. If it feels like the tires aren't gripping and bouncing around, let some out, and if they feel squirrly, add some... but only in 1 or 2 psi increments. A little goes a long ways with DH pressures. And be warned, you can pinch-flat a UST tire riding DH... I've seen it happen.
It's very personal preference type of thing. In my experience I started out with as low pressures as I could get 18 or so. Once I started getting faster the pressure started to go up to stop flats and keep the tires feeling like they would roll off the rims in the corners. After 8 years of racing DH I start at 30 with 2.35 Kenda Nevagals and let air out depending if I feel too bouncy or I'm feeling a little lazy and need more traction to make up for my incompetance. 27 seems to be a sweet spot for me.
If your just starting out go as low as you can go and add slowly until you feel like your loosing traction. 20-25 is a good place to start.
I don't run below 32psi for Kenda 2.35's in any tread pattern for downhill riding/racing. Tire feels too soft and always feels like it's punctured if i'm sub 30psi. Funny part is I only weigh 140lbs geared up.
It would be nice if he posted where he lives... his comments about having a set of "race weekend only tires" is interesting... I personally seen tires torn to shreds after 1/2 a day of practice at Plattekill...
I'm thinking probably West coast even though I think Pinkbike is Canadian. Soft puffy high speed dirt. A set of tires is usually destroyed in one weekend at Diablo. Plattekill seems to last a little longer for me. I get 8-10 sets of tires for a race season.
Interesting... I always found the loose, sharp shale at Plattekill harder on tires than the rocks at Diablo...
Of course, I'm still running the same set of DH tires (Comp 16's) I bought at Snowshoe back in 2002... amazing how long a set of tires will last when you only use them a couple of days a year (on average).
Learning not to brake-drag helped a lot as well with tire longevity, as well.