Understood, 'V2 is a speed you fly at with flaps down.'
Ignore the flaps thing, just take the V2 figure the manual gives you at the appropriate weight then completely forget it happens to be called V2.
Then add 20 kts
Then fly that number on the speed dial in the CLEAN CONFIG.
Best L/D occurs at approximately whatever the V2 figure is in Knots plus twenty - (this gives you the 737-300 CLEAN best L/D approximately).
Other jets, configs etc will all be slightly different.