Valve Cover and Push Rod Q's

i have stock valve covers i am going to polish but not sure if they will be tall enough for my valve train _ 1.72 RR's, heavy springs, comp cam xe-270-hr-12 or part number 35-312-8 cam for 1.7 RR's, INT .544 and EXH .566. (also hope this will work with stock pistons.) could the xe-270hr-14 work with the 1.7RR's? its the same cam as above but supposed to be used with 1.6RR's. also whats the proper way to measure for pushrod length. i think the stock might be ok but not sure. i dont want to use them with the heavy springs and aggressive cam anyway. thanks for reading, hope someone can make sense of my incoherent rambling.

surley somebody knows something

how can i check piston to valve clearance? what tools are needed? also whats the process of checking pushrod length? assemble valvetrain, turn one rocker, insert adjustable pushrod, turn rocker back and check length? what kind of free play / tolerances do i need for piston to valve and push rod to rocker.?