cloneable oEmbed fields doesn't treat empty data as "NULL" when saving it both on core table and custom table. instead, it's saving "a:0:{}" value.
Also on meta builder please add 1 field where we can insert our custom table name and also include it when user need to export the code (you can show it only when user has the Meta Custom Table extension activated).
"'storage_type' => 'custom_table','table' => $input[usr_table_name]".
Thanks, great framework so far!