Valve guide seals are not a substitute for proper guide to valve stem clearance. It's also possible to seal things too well, resulting in the guide running dry, and wearing rapidly. When that happens, there's not a seal made that will control oil loss, regardless of its design.
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!