how to use smaller markers

[plunk]

As you can see here http://www.allergie-weg.nl/therapeuten/index.php?option=com_content&view=section&layout=blog&id=7&Itemid=86: 100 markers upon the Netherlands is a bit to much. So I would like to use the smaller markers.

Using smaller icons requires a smaller 'hit-area'. I customized my markers, so I could easily design a smaller marker, but if I do, the area above my marker is still 'hit area'.

What can I do?

Thanks!