I have been working with the emulators for some time (long before Race Tech even knew about using them in the ATC 250R...heck I even helped them with the set up...lol) and have found that the best springs for the ATC 250R are the .52kg. Race Tech will recomend the .47kg but they will most likely be to soft. ATVonDemand had Race Tech do the mods in there ATC 250R build and went with the .47kgs and were to soft. I recomended the .52kg springs and they liked to results. I have the part numbers for the right emulators and springs somewhere and can post them if needed. The emulators also come with two springs...blue (installed) and yellow. I recomend the yellow.
If you just want to do progressive suspension springs, I recomend 15 wt fork oil at 5.5 inches from the top
Also, someone said they mixed oil at 50/50 ratio to get a middle weight. Unfortunatly that is not how it works. There is a formula for mixing fork oil weights that I too can dig out and post if needed.
The 85 ATC 250R has 21* of rake, the 86 ATC 250R has 21.5* of rake. Of course it is all relevent to the size of tires and your ride height as the will effect your rake.