I have always created Service Type documents for my open documents.
My opening process is:
1. Goods Receipt for Opening Inventory (Quantity and G/L).
- This can be done through the Inventory Count as well
2. Service Type documents for Open A/R Invoice, A/P Invoice, GRPO, and Delivery.
- Basically any document that creates a journal entry should be posted as a Service Type document.
- This takes care of all of your Accounts receivables and Payables.
- The Line Item Description I add the parts and description so that they can be identified.
3. Open Purchase Orders and Sales Orders are the only documents I place as Item Type documents so they can still go through pick and pack.
4. Then perform opening balance on any other accounts
5. Adjustments through journal entries.