Now I'm home and can explain it a bit better. If you look along the bottom of the two long flat bars from the rear of the truck they should line up perfectly with each other. Parrallel to each other and the ground. I like to take the time to get it spot on.
With the cab I had a mechanic tell me half way between top and bottom but I found this to be too low. The rear of the sleeper was low and it looked funny plus rode rough. I'm quite a bit higher than that point. I've had some people say put a level on the sleeper after doing the rear suspension and get the cab perfectly level. Make sure the ground is level too.
Personally I don't think any measurement is needed, they're both easy to do and probably the easiest suspensions to get right out of any truck I've owned.
With the cab I had a mechanic tell me half way between top and bottom but I found this to be too low. The rear of the sleeper was low and it looked funny plus rode rough. I'm quite a bit higher than that point. I've had some people say put a level on the sleeper after doing the rear suspension and get the cab perfectly level. Make sure the ground is level too.
Personally I don't think any measurement is needed, they're both easy to do and probably the easiest suspensions to get right out of any truck I've owned.