Hi,
Thank you joaoFerreira for finding the solution and sharing it with us!
To achieve effect growing width, you should also set
borderWidth: 0 on the series.
Here is a full demo:
https://jsfiddle.net/BlackLabel/6nrh1zt4/
Regarding the second question, I gave you the answer in the separate thread you created.
viewtopic.php?f=9&t=47589#p171435
Let me know if that was what you were looking for!
Regards!