While messing with my steering stem I had the forks off.
When I redid the seals on the '96, the oil came up to just below the springs.
I looked at the '88 and the level wasn't near as high.
So either it leaked out (highly possible), wasn't filled correctly, or something is different.

So that gives us 2 possibilities for your problem, either the fluid is low or your caps aren't sealed.  I'd add oil to the top of the springs and work from there.  Adding a couple of ounces at a time and see how it feels.  This will reduce the air volume a little at a time and do the same as adding air pressure to the forks.  You'll still have the same issue with blowing out the seals if you exceed the capabilities of the seals.  But adding a couple of ounces at a time will allow you to sneak up on it.