DPI you should leave as 96, Min zoom you could also probably leave at 12, depending on the size of your map, and maybe try 20 for maximum zoom, which is what we use when exporting MBTiles from ReefMaster. You could potentially increase this if your source bitmap is very high resolution - every increase in zoom level by one will give you 2x the resolution and 4x as many tiles in the next layer. The meta tile size is probably not something you need to worry about - I believe this is only used when rendering MBTiles tiles, and is more applicable to vector based maps.