Stock head gasket is fine out to about 8'th over (2mm).
Attempts to use no head gasket at all will result in failure, most likely - including oil leaks and compression blow-by.
Very risky to use sealants around the two (rider's) right engine studs, as they are the oil passages for the entire top end. Marginal oil pressure is one of the 450's weak points, be careful about it.