Originally Posted by UniChris

Given my narrowest tires are in the 40's I'm the wrong person to ask.

But I'd think that a rim for a 23 or 25 tire would be under 20mm in width at which point drilling for a Schrader cuts out at least half of it. It would also seem to require the valve to tube seal to pinch into a very narrow inner width.

Granted, the inner web of beam like structural members often does have lightening holes in such a position.