ball and cup pushrods size for a 360

I need to ride this post as I am doing the same seach for my ride. I have the 340 and a set of 1.5 rollers that I am installing. I was under the impression that you just have to measure it with the special pushrod tool. I don't think a standard size is the safest way to go. It sounds like the simplest, but has that always proven to be the best? I don't like to extra work but I think investing in the tool is the way I will go.