I bought new 6 discs and the st screw holes don't match, should I drill the hubs, or is this ok as long as the lugs are torqued good?

-6 disc's holes will not line up on drilled 4 hubs. Not sure but they might work properly IF the screw holes were indexed to the -6 rotor prior to drilling.

I had this same problem and drilled one hole which keeps it straight enough to put the wheel on.Once the wheel is on it won't move.

I have run mine for a year with the rotor loose - held in by the torqued wheel. I will get around to drilling and tapping it but for now it works...