slope (or angular) dimension with percentage as the unit
I don't know of any built-in way to do that. If using a Dimension, I suspect it would need to be a routine that would impose a text-content override on a selected angular Dimension. And if the angle was changed, it would be necessary to run the routine again to update the override.
Doing it otherwise than with a Dimension [e.g. with Text, or a Block Attribute], the number of picks involved would be slightly reduced. But I suspect the number of picks to update such a thing after changes would be slightly increased [pick the sloping thing and the Text/Block, rather than just picking the Dimension].
Such a thing could use parts of ReportSlope.lsp, >here<. One thing that does, which I assume would suit your needs, is to report the absolute slope relative to the horizontal, regardless of in which direction the object it's reporting on was drawn. [A Line drawn at 330° gets reported as being at a slope of 30°.] It never gives a negative result or one greater than 90° -- a slope is a slope, and whether it's "positive" or "negative" depends on which direction you're going on it, and would not be part of what you want drawn.
Here is the results using a simple example block. The ATTOUT command was used to export for use in Excel. Excel results were saves as a .TXT file and ATTIN was used to import and update the block data after processing.
