(I assume you dont want the game only to run on your PC)

Better use LOD where the user can change the LOD distances
by themself.
There is no perfect Polycount for PCs, as the systems have too
different performances.
The best is to give each user the option to tune
the graphics themself in the options.

You could also offer an option to adjust the LOD and other
effects, so that the game runs on a minimum Framerate automatically. (where the game changes the LOD dynamically
given the current FPS)