wrong. IF you know what you are doing....you will be able to set them and be done with it.
You can set them with it running and when you are all done and there is oil everywhere and you have brain damage from all the smoke you inhaled. The preload will still be wrong.
Lots of people think you can set a motor "by ear" but in the end all you end up with is a wiped out cam.
Same thing as people who think they can set the timing "by ear" all you end up with is a motor that runs lean and hot and burns up plugs.
You need to use numbers and proven techniques that set all the lifters the same and to the manufacture specs.