New head gasket 25hp Johnson

[oldie1962]

One little job gets bigger
I have to remove my head after breaking a couple of bolts on the water jacket whilst renewing thermostat. Head removed and bolts removed with OXY, lube and patience.
I have cleaned and sanded head (gl*** sanding) to ensure head is flat, thermostat fitted and new waterjacket gasket fitted,
Question: Should I use any gasket sealer when I fit the head back on or keep it all clean and use compression to bed the new head gasket. Also should I retension head after say 10 hrs use.

Thanks ****ie

[highcountry]

I never use anything on a head gasket, but I don't think that a little copper coat would hurt a thing. As for the re-torque I would.