If you want to change the width of the all the edges in the graph, do the following. (These instructions are for version 126.96.36.199 of NodeXL.)
1. Click the Graph Options button at the top of the graph pane. If the graph pane is narrow, the Graph Options button will be "hidden" behind a down-arrow icon.
2. In the Graph Options dialog box, select the Edges tab.
3. In the Edges tab, set the Width to something other than the default 1.0.
To make this change "stick" for all new workbooks you create, do this:
4. In the Excel ribbon, click NodeXL, Options, Use Current for New.
To find out more about how NodeXL options work, do this:
5. Go to NodeXL, Help, Help in the ribbon and view the Working with Options topic.
I do not understand your second paragraph.