Tony, according to this thread he already has made the spacers and installed the Sonic springs and by backing out the pre load adjusters all the way he lowered the front down which does nothing to make the front softer. If anything the added weight made it a tiny bit stiffer. Probably corners better though.
He is talking about adding the emulators and yes , that will raise the bike up about 1/4 inch. Nothing a cheeseburger and a couple of beers cant fix.
Comments were made before reading the 2nd page of the thread..... But in the end my comment is still the same; you will need to make new spacers, spacers that have had their overall height determined after taking the height of the new emulators into the equation. As you have explained pre-load has nothing to do with the stiffness of the springs; pre-load affects overall ride height and/or static sag.
While I don't think this is his issue but a spring rate that is
much too high for the weight or the bike and rider can cause a harsh ride. Think about an old 3/4 ton truck with no weight in the bed it will ride rough but once you added a bunch of weight into the bed it smoothed out an rode real nice.
Here I'd be willing to bet that lighter weight oil will soften up some of the harsh ride. As would the drilling of slightly larger holes in the damping rods; these were all old tuning tricks used before the invention of Cartridge Forks or Cartridge Emulators.
Another point to bear here is that if your oil level is too high that under heavy compression you can cause the fork to "Hydraulically Lock" and ride harsh; one must maintain a cushion of air.