This topic has been kind of talked around already, but I had some specific questions.  The manual says to measure the oil level with no spring, fully compressed.  The level should be 3.9 inches from the top.  The instructions from progressive say that the level should be a maximum of 5.5" from the top.   First of all, does that mean 3.9" is ok per the sheet.  This doesn't make sense, because if the progressive spring displaces more oil, then I might have way too much oil in the forks with the progressives.  

Secondly,  i guess the spacer is on top?  it really doesn't matter physically, but do i measure fork oil with the spacer in or no?  With the extreme difference between stock and progressives there is a lot of error here.  I'm inclined to measure the oil with the stock spring and spacer in, fully extended so i don't have any parts sticking out the top of the tube, and then make sure the oil is at the same level with the progressive springs in.

Here's a question though.  What difference does too high or too low fork oil level make?  Too high and you blow the seal out?  Too low and no damping?  Should I even be concerned?

it would seem that with progressives you'd have too much oil but I havent replaced or removed any oil since installing the progressives and 4500miles later they're still fine.

Also, how would you measure oil level with the spacer in if the springs aren't in?

I put in progressives, and didn't touch the oil level. I've had no problems. I worried about the same thing when I put them in, but no worries! They are definately worth it!

this may be the same, but local shop owner said 12.9 oz of fork oil when i replaced the oil seals, nothing about distance from top.  should i be worried?  haven't put in progressives, are they and stock specs the same?

Here are some interesting links on fork oil that I found in my research of this

Executive summary..the air between the fork oil acts as a nonlinear spring that hopefully keeps the fork from physically bottoming out the internals.  Too little air and you don't get full suspension travel.  Too much air and you might damage the forks on a hard bump or doing stoppies.  It makes sense to me.  It has a method for checking the level.  Pretty cool.

http://www.luna-computers.mcmail.com/forkoilfaq.html
http://hondaxr.com/tech/ktm/forkoil.asp

Neat.  Another thing to tune!

I put in Progressives without any spacer.  Fork cap screws in and acts as a spacer.  I didn't touch the oil and it rides just fine.