I've never seen a recommended spring load on a cam spec sheet so no surprise that it is not there. There is a lot more to actual load on the cam than just the spring load times the rocker ratio.... that is just the static load part. The dynamic load part comes when the valvetrain is being accelerated into motion from closed to open in each cycle; that adds another force that is highly dependent on parts' speed (RPM). Plus the spring loads are also dependent on what the valvetrain needs to not 'float' all the way up to the intended max RPM's ... i.e., all the parts stay in contact and in motion together. So the cam mfr's just give you a recommended spring to do the job, and if you keep close to those spring rates and closed valve loads, you should be OK.
