Based on the Park conversion chart 25 deflection units is 121 kgf for a 2 mm spoke, 173 kgf for a 1.7 mm spoke, and clear out of the ball park for a 1.5 mm spoke. That's more than what is recommended for any rim that I'm familiar with, and I run some pretty high tensions.
The tension differential between the drive side and the non drive side is whatever it takes to get the rim centered. From my experience with typical 9 and 10-speed road wheels the non drive side spokes have had about 63% as much tension as the drive side. The trick is to get enough tension in the non drive side spokes so that they don't break at the "J" bend from excess flexure and at the same time not exceed the recommended tension for the rim (by too much) with the drive side tension and also have a centered rim. I usually exceed the rim's recommended tension but not by too much, so far no rim failures.
Last edited by Al1943; 06-03-10 at 02:55 PM.