Thanks for the tips (and pardon to resurrect an older post... but figured it's best to keep the same topic in one place).
Using the category ID field and the custom attribute as outlined in the very helpful post by Stanislav above. The result is that I can now drag and drop the items/rows in the table on the front end, but the order change doesn't actually get recorded in the database. I.e., the change takes no effect. I don't see any javascript errors in the console, except for "Duplicate form field id in the same form" - don't think that has an effect here, does it? Also, I can't actually find two same field ID's in the rendered page HTML so not sure why the console is throwing this error/issue.
If you can think of anything else to check on, please share. I have followed the tutorial listed by the OP above. Search used to work, but stopped at some point w/ one of the Seblod 4 versions. Same results w/ Seblod 4 and 5.