Hi,
You can
1. Define line layout and select the same in appropriate layout by clicking on Editing options ask users to make entry through Fast data entry screen through FB01 transaction.
2. You can assign the layout by giving layout created against the FZ1 (FI: Invoice/Credit Memo Fast Entry Line Layout), FZ2 (FI: G/L Account Items Fast Entry Line Layout) and FZ5 (FI: Document Parking Fast Entry (G/L Accts) Line Layout) in the user master under Parameters tab.
3. Please remember in this case don't give Editing options and SU3 authorization to users to users as they will change the same so there will be no use of line layout.
As far my knowledge changinging screen layout through SHD0 would be at transaction level and cannot be restricted at user level.
Regards,
Tejas