The latest version limits throttling to the current tab, so if you open the bookmark in a new tab, the macro will always be executed.
You can add a delay while recording by clicking "add step" in the bottom red bar and selecting "Insert Delay".
Any action that leads to leaving the current webpage will end macro recording.
You can import the exported JSON file by clicking "Import Macro" on the top of the "Manage Macros" page.