Morooka mst 2200

Hi, I'm new to the forum. I recently purchased a 1990 Morooka mst 2200 and have been trying to find information on proper track tensioning. I found an old manual online that indicated the measurement between the center of the idler wheel shaft and the slide holder or yoke should be 435mm plus or minus 5mm but as things wear (idler wheel) that measurement can't be trusted because you're going to have to keep adding grease to the tensioner, extending the idler out. There must be an industry standard measurement for track sag or something that can be used regardless of component wear. I read on a previous Morooka post that lantraxco was the site expert so hoping he sees this! thanks.