LIFTER PRELOAD

I'M CHECKING FOR PUSHROD LENGTH ON A 360 AND I HAVE MY LENGTH OFF OF THE CHECKING PUSHROD. I MADE A CHECKING LIFTER AND MEASUREMENT IS OFF THE BASE CIRCLE OF THE CAM. ENGINE HAS STAMPED STEEL ROCKERS, BLOCK WAS DECKED .010, THE J HEADS MILLED .030 AND A STANDARD "BLUE" FEL-PRO HEAD GASKET (DON'T HAVE MY UNCOMPRESSED AND COMPRESSED THICKNESS IN FRONT OF ME). THE LIFTER CALLS FOR A .30 TO .40 PRELOAD (LUNATI MICROTROL) BUT MY QUESTION IS IT SAFER TO ADD .30 TO MY TOTAL PUSHROD LENGTH, .40, SOMEWHERE IN THE MIDDLE OR OTHER?