SharePoint 2013 timer job workflow to process items in a list: lessons learned

Here are some gotchas,   

• could not get a null date filter to work 
• only the request header, ResponseContent, and responseCode is needed to use the web service activity
• Use HTTP Get
• set header
• ACCEPT:  application/json;odata=verbose
• Content-Type: application/json;odata=verbose
• not needed:  X-RequestDigest: $("__REQUESTDIGEST").val()
• get d/results
• the values for each items needs a parenthesis like Get (0)/fieldname 
• not all fields are accessible from the normal json call for example:  http://yoursiteURL/_api/web/lists/getbytitle('ListTitle')/items
• by default it will only return 100 so can add ?$top=5000
• so you can call the web service to return all string by calling the web service with the url for each item:
• ([%Variable: index%])/FieldValuesAsText/__deferred/uri  
• This will be the url to call to return fields as text like the people names for emails, etc
• A good way to view the fields for the json call that i used:
• firefox
• add-ons:  i used the following  
• JSONView 0.9
• Modify Headers 0.7.1.1
• only thing to make this work is to click on the options on the Modify Headers options, then add the action Modify, the name is Accept, the value is application/json;odata=verbose
• all you have to do now is just call the service and the json data will display in firefox. 
• SWEET!
• this is very useful for field names
• Have fun folks.  
• if questions, let me know.  this is one of the best new features of SharePoint 2013.