Synthetics still don't have the adhesion power as a conventional racing oil with "lots" of zinc compound. The former quickly drips away leaving bearing and cam surfaces relatively unprotected. I'm sure synthetics will improve in this regard in short order. ***Maybe there are products available I'm as of yet unaware??
NOTE: Modern conventional oils have less zinc additive due to issues with catalytic converters. If you run cats you'll want to look into this.
Having said this, I'll be running synthetic but will have a full roller motor plus a lube pre-charging system that will be activated for a few seconds before start-up. I'll also have an ignition disable switch so I can crank the motor a about 5 seconds to evenly lube the bearings before startup. Yeah, I know I'm a bit anal-retentive.