I personally like my throw meter because it's easy to clip it on & measure everything accurately. Before I had a throw meter I would just hold a ruler up & see how far up & down they'd move. Not as accurate, but certainly functional in my opinion.

If the manual only gives you the throws in degrees then you can break out the old Trig calculator to figure out how many inches that would be, or you can cut out a piece of paper with the proper degrees on it & hold it up to your surface to compare.

Either way you certainly want to get as close as possible to the manuals recommendations.