Is there any way to preview how my structured data will actually look on Google? The markup helper only gives the HTML code, but I don't see anywhere that gives a preview of what it would look on Google Search.
Am I missing something or they did removed the preview tool?
The first version of the Google Structured Data Testing Tool was https://www.google.com/webmasters/tools/richsnippets. It showed search result snippet previews.
This now redirects to the second version of the tool: https://developers.google.com/structured-data/testing-tool/. It no longer shows the snippet previews.
If the new tool detects structured data that Google makes use of, you can click on Filter by use case and select a use case, which shows the link (what's this?) where you can get more information about it. This page typically displays an example snippet (but of course only with general data, not your specific example).