Note that 50/50 shocks, (a baseline for tuning), in the setup menu corresponds to 4 in bump and 1 in rebound.
This is because the setup menu has a built-in 1967 F1 historically accurate 1:3 ratio of compression to release.
So, 1/1 is softer than 5/5, but for both the ratio of bump to rebound is 1:3.
Here is a link to an easy-to-read shock tuning guide:
Couple of quotes from the guide:
"And one last general guideline to keep in mind...
10. In general, stiffening one end of the car will reduce the mechanical grip on that end. In other words, when you raise the spring rate, increase sway bar size or stiffness, stiffen the bump or rebound of a shock, install firmer bushings, etc. you will reduce the grip on that end and decrease traction. To increase grip you must lower the spring rate, increase the sway bar size of stiffness, soften the shocks, use softer bushings, etc. (Tire pressure is another contributing factor, but that's a discussion for another day.)"
Then later on regarding tuning rebound on Koni shocks:
"It should be noted that too much rebound on either end of the vehicle will cause an initial loss of lateral acceleration (cornering grip) a that end which will cause the vehicle to oversteer or understeer excessively when entering a turn. Too much rebound control in relation to spring rate will cause a condition known as "jacking down." This is a condition where, after hitting a bump and compressing the spring, the damper does not allow the spring to return to a neutral position before the next bump is encountered."
Hopes this helps...maybe some more later.
Edited by John Woods, Feb 22 2015 - 11:54 AM.