Q1 – There is a way to do this so you will dynamically always get the top.
Instead of setting the rows to ‘Increasing’ set them to ‘Decreasing’, but change the Y axis to ‘Reversed’. This means the numerical values underlying the category labels will be decreasing down the y axis. Then you can ‘Restrict’ the Y axis so it does not go above the rank you want, with 0.5 added to get the look correct.
Here is an example ‘Top’ is a slider variable, so you can easily change how many you want to show and it all updates automatically.
Q2 – Use a wildcard to filter on a phrase with a mask. Spaces are fine and you do not need the quotes around the phrase. In fact, if you put quotes that will not work as the filter will look for the quotes too. Hope that works for you!