Pack Mule, Just after acquiring my boat,I think managed to glaze mine by running it for maybe 8 hours no load, until I realized the eutectic refrigeration compressor had died and was drawing zilch. There was blue smoke wafting from the exhaust and it was using oil. I realized what was happening and gave it other loads, but it stayed smoky.
I researched on the internet(uhoh)and came up with a diesel engine additive(uhoh snake oil alert!) made by reputable Australian engine oil supplier Nulon,which Nulon claimed would remove glazing if used at double strength. And it did. I hear all the background chortling laughter, but it worked. The thing stopped smoking and using excessive oil. That was 7 years ago, the Onan 6.5 3 cyl genset runs fine and uses little oil. Out of respect and because there is a possibility of underloading I still use the stuff in the genset oil at the normal dose,I don`t bother for the main engines, no glazing there.
If you believe any of that, try some internet searching. No way you will find that Aussie product over there, but there may be something else similar. And the advice to run at 80% load for an extended period might be right on the money too.