this gets tossed around constantly on Pirate, and everyone has their preference. the preferences typically range from 80% to 160%
as MaXJohnson reffered to; unless you're cutting through the floor, or hanging the lower links pretty low, it will be difficult enough to get your AS under 150% or so, so just get it as low as you can, and if there is any place you can make the brackets have extra holes to play with different values, do it.