I did not find any information on your spreader.
You might just run your own test: add a set weight of fertilizer to the spreader, set your pto rpm and forward speed.
Run machine until bend is empty: measure width and length of ground covered.
I realize this method is very red neck, but at this point, unless you can find a similar scale this may be the best you can do. Run two or three test at different settings.
I do not understand why there is no data on this spreader?????