I've had cams that were out by miles......the lengths all over the place.......i'm sure there is a spec on the proper lengths. I generally customize what ever I have to to get the timing chest contents up to par. You can shave a whisker off the inner end of a cam if it seems too long, but like you say, you need to get the followers as central over each lobe as you can........This can also be difficult if the followers are wider than the lobes........The shim washers are great, but far from what is really needed.......Main problem is their thickness is often either too much or not enough......This is where you need to improvise.......using whatever washers it takes to do the job.......They need to be hard ones as well.......A lot of the supplied ones are stainless and way too soft. On the smaller spindles they become cup shaped and this makes the shimming of the steady plate a right pain. Often I will trim down the length of the long steel tube spacers and simply shim up the difference generally on the inner end of said tube, even linish down the width of the follower if this helps, it pays to add shims to the inner side or else they will fowl on the cam pinion.......Get the steady plate as flat as possible to avoid any strain on the spindles, they are only a mild interference fit, the cam spindles not more than 0.001" and the smaller ones less again.......these will shift when the engine is at full temp on a hot day, the cases can get up 130 plus degrees Celsius when checked with a temp gun between the cylinders. Using loctite on spindles and the like is ok, but be very careful to clean up any left over that surrounds the spindle bore, if you slip a follower over the spindle, the loctite will quickly anchor it to the spindle and can be a right bitch to remove. Good idea to set up the cams and their pinions meshing with the large idler adjusted up to both cam pinions and rotate the large idler several times and make sure there are no tight spots.......this will cause a "Hunting sound" within the timing chest when running, so adjust the idler to run freely at this tight spot if needed, the small amount of backlash between the gears when turned will do no harm or create too much noise when it is running. If the timing chest is set up well and the rocker gear in the heads has the ET 100/1 mod carried out, plus no excessive side play in the rockers/bearings the engine will run nice and mechanically quiet........Good luck with it all.