Nope, no need to use them, if you've got the machined guides and positive stem seals. Dual springs are only necessary if you're running above 7,000 RPM. Do you plan to run it that fast on a routine basis? If not, all you're accomplishing is a lot of camshaft wear, in a hurry!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!