Prefill visual selection first

The cookbook shows <leader>ss to use the last search first then fallback to visual selection for prefill, can you show how to switch it so first it use visual selection and if there isn't then it can use the last search? Other issue is if I do a visual selection and search with * the search starts with \V and if I enter <leader>ss there's regex parse error `unrecognized escape sequence` because of \V pattern.