SCAv1 and SCAv2 both mitigate CVE-2018-3646, however SCAv2 does not mitigate Intra-VM Concurrent-context attack vector process information leakage.
The User's Guide was published before SCAv2 was available, thus it doe not contain any information about this new feature. At this time we accept submissions which use either solution for mitigation.
I suggest reviewing the whitepaper we published for a detailed analysis of the performance impact of both schedulers. Performance of vSphere 6.7 Scheduling Options