On the logarithmic scale, the issue is with your range. Since the log of 0 explodes to negative infinity, the chart will attempt to max out the range and your values will disappear.
Instead, set the min to a reasonable low value, or leave it blank so the chart will automatically set a lower limit based on the data (you can still specify a max):
For the linear chart, you'll have to play with the appearance.grid.minDistance property of your axis:
If you set it to a larger number, the space between gridlines will increase; I believe a value of null will automatically pick a grid spacing:
Note this is a visual distance so if you then scale the actual chart component it will adjust the grid numbers to maintain roughly the same visual spacing (relative to view size):
