As far as I know, meshlab has several algorithms for reducing mesh objects which you can refer to. In addition, meshlab also has capabilities of batch processing for multiple objects :)
Generally, In every software mesh size is defined as dx, if you can find the mesh size, for an example as 1cm, your mesh size would be X min=0, X max would be 1. After that you can change the number of cells in X direction/axis. If the default value is less, change it to a higher number of value. Every software as its own mesh setting, which can be found in User guid of that software. Hope it helps, Cheers !