I've used the Rustoleum spray lacquer on hand plane handles and it has worked well for me.  It dries fast and has been durable with frequent use.   I've never applied it over Danish oil.  I wonder if the the DO was not cured enough yet.  I could see that affecting the lacquer.  Just thinking out loud.  

--Nathan, TX. Hire the lazy man. He may not do as much work but that's because he will find a better way.