Insert redirect: step back from this for a moment and think about it. The important thing to realize is this:
the redirect link is created before the record is inserted
this means that it is impossible to set the redirect link to pass the product ID before the product has been inserted to the database.
You should redirect the insert to the detail page, then if you want to update, click the link to load the update page, it would require hand coding to look up the inserted product ID to be able redirect to the update page.
for the update, you are trying to update multiple records, so you will need to use the update multiple records behavior, not the update single records