Its not as complex as you might think TBH Jim.

VSR simply closes the gap up on a head like yours so should make little noticeable difference to the way in which you set the tappet clearance's.

VSR is generally due to lack of lead in the fuel. What it does cause is badly seating valves and excessive HC's with a consequencial increase in teh amount of required fuel to give complete combustion.

Set the followers properly (With pressure applied to the upward thrusting side) and cross your fingers for relative quietness.

Have a great evening