This page may help a little. It doesn't talk you through setting a default for all new documents, just all pages within a document:
Combining a few posts from that URL, what it basically says is...
Steps
- Add a tool called Document Stencil to your toolbar/ribbon
- Draw a few shapes, add connectors, etc. Basically, add the element(s) you want to modify the default style of onto the page
- Click on the Document Stencil check box tool. This will display the Dynamic Connector master in the Document Stencil
- Right-click on the item you want to change (e.g. Dynamic Connector) in Document Stencil, Select Edit Master -> Edit Master Shape to open the Editing mode. This will display a basic version of the item you want to edit
- Right-click on the item and select Format Shape
- Make your desired changes
- When you are finished, close the editing window (NOT the application - use the smaller X at the upper right)
- When prompted with a message like "Update 'Dynamic Connector' and all of its instances?" - click Yes.
Result: The existing connectors on the page change to match, and new connectors created using the tool will use the same format. This needs to be performed once per file. Not the perfect scenario of a default for all files, but a lot better than modifying drawing items individually or per page.
Some caveats:
- If you are creating connections from the Connector tool, they should all be based on the same Master. You can change some options at the Master level, and have them inherited through a drawing - with one big caveat. Anything you have already updated manually will no longer inherit from the Master, as the change that you made in the UI is stored in the copy of the shape.
- Note that this will be used for all copies of the master, however, Visio has to set each line end separately.
- You may want to select both ends to set the correct type, and then turn them off as desired in your drawing.
You can also refer to this thread http://answers.microsoft.com/en-us/office/forum/office_2010-visio/how-to-set-default-connector-style-in-visio-2010/ce95262a-72bb-46a5-9265-0297af2151a5?msgId=9a5c12dc-9e72-4832-bbe7-dad6b35b8714