I made a brush of rivets and I was able to space them out nicely but being able to paint them in a straight line has been a problem. Is there any help in this area

.. using what? Krita? I think you put this in the wrong forum (this one is for discussing the kde forum itself).
If it is Krita that you are talking about, it has its own set of sub-forums under KDE Software > Graphics & Multimedia > Krita: viewforum.php?f=136, probably the Krita News & Discussion forum would be the most appropriate.

If you could provide some screenshots and examples of what you are talking about, those would be much appreciated.

I was using gimp for making the rivets. There is the issue of spacing the rivets that is also a concern. Is there a setting for the spacing of a brush