I've had about 60 head for the past few years and those go through 2 or 3 times per year. My 150-180 is a far cry from your 9000/yr through the chute and headgate! 

I can see where pulling a hydraulic valve lever would be a lot easier on the body!

An aside: I cant remember the last time we used the squeeze. Usually headgate and occasionally the neck sweep hold them still enough and long enough for the vet to do his thing.

With the drought and hay shortage I'm down to about 25 head for awhile until I rebuild by saving heifers so my current chute/headgate scale setup should do just fine!