push rod length help

If I could interdict with a question on this matter. Does the "straight line at 50%" apply when setting up a set of Hughes rockers on a BB. I ask the question because I'll be installing a set on my 383 in August and I'm using 452 heads. Personally, the first time I heard of the straight line was on the Hughes website and yes I know the importance of getting the correct contact between the rocker roller and valve stem face through the entire sweep. For that purpose and just in case I have a set of rocker shims.