TotalBoat Halcyon varnish should not have any problems when applied directly over a lacquer finish. The lacquer must be completely cured, for at least 48 hours or longer, any surface waxes, oils, dust, dirt or other potential contaminants must be completely removed, and the surface should be lightly sanded with 320-grit sandpaper prior to applying TotalBoat Halcyon.
It is highly recommended to always attempt a test sample on a separate sample piece, or in an inconspicuous spot, prior to attempting this on the main project. Do not continue to use TotalBoat Halcyon if it does not achieve the desired finish on the sample.