Question
If choosing the method of soaking in hot water to scarifiy, how long,and is there a water temp. that is best?q8u31

Answer
Hi Jim,
Thanx for your question.  All of my references indicate that persimmon seed are difficult to articially germinate.  I do not use hot water to scarify however you can boil the water, remove from heat, put the seeds in the boiling water and allow them to remain there until the water temperature falls to room temperature.  Seeds must be sown immediately as they do not keep well.  This reference from Oklahoma State University is the same method I would use.

Persimmon (Diospyros virginiana) Propagation of
persimmon is considered difficult and germination of its seed
uncertain. The seed is dormant when ripe. The cause of the
dormancy lying in the embryo. Stratification at a low temperature
for a period of 20 to 40 days or fall planting of unstratified
seed has been reported effective in breaking dormancy and
forcing germination.  (Low temp = >40F)

I hope this helps.
Tom.