[Solved]-Utilizing full height in highcharts bubble chart-Highcharts

there are option to set the min/max bubble size. the default is that the max size is 20% of the hight of the chart. you can change this in plotoptions e.g.:

 plotoptions: {
        linewidth: 0,
         bubble: {
                minsize:2,
                maxsize:"50%"
         }
    },

note, you can also set the max as a number of pixels.