One tip I use is IF you have found the right balance of front to rear springs to suit your current configuration, use the ratio of the springs for the oils also. You need to know the actual rating of the springs you are using (that's why I measure my own!) for this to work of course. So if your rear springs are say 10 percent lighter, you use 10 percent lighter oil. Works for me every time, especially usefull when you get the rear of the vehicle right and can't identify what the front is doing/requiring. I find for my 2wd Buggy I need approx a 2.5wt difference as where my SCT needs 5wt. Hope that helps!