Ruler/Line ability for 2d view
The idea is the ability to draw a straight line in the 2d view, which you can move around freely, rotate etc.
This line can then function as a kind of measuring stick, or ruler.
Which can help you place things like bolts perfectly along a straight line, but at uneven spacing, or spacing which is more than 400 units apart.
Bonus features could be the ability to add points to the line, like evenly splitting it into 5 parts, free moving points or symmetrically placed points etc.
I think this can function amazingly as a guide, either as a temporary purely visual helper tool, or maybe even as a flexible generator which would allow you to change the placed "screws" at will.
I attached an image to help explain the idea