Have the same problem here http://www.sportdorpwarns.nl/. The new update renders min width 220px although.
Before the update it worked ok, adjusting to 200px or to the iframe and the whole sidebar, dunno did not look at it at that time as it worked allrigth. After the update it keeps 220. Since the 220px is generated by the widget on twitter side there is little to do with it, and it doesn’t adjust to the sidebar width thus. Responsive design is also worthless with such a setup.
It would be great to be able to get here min-width: 200px instead of 220.
If anyone finds a solution please let me know.