Valvetrain Geometry
It would seem to me that a mid-lift geometry on both sides of the rocker arm would be the 'best' place to start for most applications. This would mean the line that connects the roller tip center to the rocker shaft center is at 90 degrees to the valve at 1/2 lift and the line that connects the center of the pushrod ball tip to the center of the rocker shaft is at 90 degrees to the pushrod at 1/2 lift. This is shown in the picture below which is taken from the book 'Mid-Lift' by Jim Miller available on Amazon or on mid-lift.com.
This arrangement gives the least amount of sweep across the top of the valve and the least wasted motion (or the highest efficiency) of converting cam lift to valve lift. Both of those are good things.
As others have mentioned the mid-lift geometry may not be what race engine builders choose to use so it may not be 'best' in all cases.
It would seem to me that a mid-lift geometry on both sides of the rocker arm would be the 'best' place to start for most applications. This would mean the line that connects the roller tip center to the rocker shaft center is at 90 degrees to the valve at 1/2 lift and the line that connects the center of the pushrod ball tip to the center of the rocker shaft is at 90 degrees to the pushrod at 1/2 lift. This is shown in the picture below which is taken from the book 'Mid-Lift' by Jim Miller available on Amazon or on mid-lift.com.
This arrangement gives the least amount of sweep across the top of the valve and the least wasted motion (or the highest efficiency) of converting cam lift to valve lift. Both of those are good things.
As others have mentioned the mid-lift geometry may not be what race engine builders choose to use so it may not be 'best' in all cases.