Where text flows across columns or pages, use the Linked text () tool to connect the text blocks. Once connected, remove any unwanted paragraph breaks at the end of each block (which will have been added before the blocks were connected.)
Reflowing the text during import is slower when the text is fully justified. To avoid this when dealing with long stories (such as a chapter of a novel) change the text justification to Left justified prior to import. The import will be faster and the justification can be changed back once it is complete.
Using Auto fit on long stories can be slower. Do the auto-fitting after the import has been done by choosing Text->Fitting... on text boxes that need it.
When translating a long document, deal with a section/chapter at a time. Since the export process requires a large amount of computer effort and memory, keeping exports to no more than 100 pages at a time will improve throughput considerably.
Enable View->Text->Boundaries to make it easier to see the shape of text boxes.
Ensure spelling language is matches the language used in the PDF - this has a big effect on hyphenation and thus reflow.
Some text boxes may need merging. e.g. Infix may split a column of text into separate boxes for headline, body, headline, body etc. In this case use the Object tool () to drag a box around these boxes, then choose Text->Text Box->Merge Vertically to ensure they become one single box.
Unless you have already reshaped a text box, Infix will automatically extend the final text box in a sequence to avoid losing text. If you reshape that box it will remember that new shape and no longer alter it.
Infix sometimes doesn’t correctly guess paragraph alignment. It may for example assume text is left aligned when it should be fully-justified. Unless you check by looking at the alignment buttons in the toolbar, this will only become apparent after a reflow. Left justification typically uses more space than full-justification which means such text may overflow. To correct this, just click in the paragraph and press the correct alignment button on the toolbar.
The text in a document may be generally squeezed a little to achieve a certain layout. Although Infix attempts to calculate the actually global adjustment used, it may not exactly match and the text may tend to overflow. To remedy this, click on one of the text boxes in a linked chain using the Text tool then choose Text->Fitting...