First of all the perspective rulers are great! I love how it previews the line you're going to draw. I'd like to suggest a feature that would make them more comfortable to place. many times you make a rough sketch and then fit the perspective rulers to it.
instead of having the ruler set and having to move each line by the handles, can it be possible to set the lines (like shift on the ruler) and the perspective guides will be created according to it? it can be much more convenient when the vanishing points are far from the canvas for example. Clip studio paint has a similar method of laying out the perspective.
another thing I suggest is being able to rotate the perspective lines and the guide will align accordingly. currently it's only possible to move each line separately or rotate the entire thing.
for example: lay out a line, then another line, and the vanishing point will be created when they intersect. also the horizon line.
if you lay out another 2 lines, a 2nd vanishing point will be created, and the horizon will change accordingly (the 2nd line set can snap to the existing horizon)
if you lay out another 2 lines, the 3rd vanishing point will be made.
Thanks! And again great program