Milling down SM 68cc CNC heads?

MLS head gaskets, .040 compressed. KB167 pistons that have a +5 cc volume with a compression height of 1.810". Block has been bored 30 over otherwise, it is stock decking etc. Can't find any details online about the compression ratio recommendation for cam but here are specs: Advertised Duration (Int/Exh): 272/272; Duration @ .050 (Int/Exh): 206/206; Gross Valve Lift (Int/Exh): .447/.447; LSA/ICL: 114/108; Valve Lash (Int/Exh): Hyd/Hyd; RPM Range: idle-4800