I think if you have more than one element to remove, or if you need precision the new [Nuke when you press X] mode is much better ( since i can't indicate which element will be removed with [Remove this] anymore).
Activate it, press [x] on a few items then [esc].

I've added a todo about the icon colors in the next update.

For the size, i am using what mozilla recommends... Don't know if making it smaller will still display well on all devices/resolutions.

[edit] This is now supported in ver 2.1, you can go to the options and remove the items you don't want.

Also the icon in the menu is has more muted colors like you requested.