Yes, configure it in code like this: jsprit/jsprit-core/src/main/java/com/graphhopper/jsprit/core/algorithm/box/SchrimpfFactory.java at master · graphhopper/jsprit · GitHub
Unfortunately, you need to find out yourself. Just conduct a sensitivity study based on your problems with varying max iterations. For very simple problems, you dont need many iterations. However, you can also use a number of termination strategies you can find here: jsprit/jsprit-core/src/main/java/com/graphhopper/jsprit/core/algorithm/termination at master · graphhopper/jsprit · GitHub. For example, VariationCoefficientTermination terminates the algo if variations of costs of found solutions are less than a threshold variation.