Do you have only a few clients with huge numbers of orders each?

Or for a large number of clients, some with large numbers of orders, some with small numbers of orders?

In the first case, your current clustering is likely fine.

In the second case, you likely want to go with the more "standard" clustering for order systems of:

Client clustered on Clientid (identity) Clientid.

ClientOrder clustered on Orderid (identity).

ClientLine clustered on the combination of ( Orderid, LineId ).

That drastically reduces fragementation but still keeps all info for the same order together.

You can use a nonclustered index on ClientOrder.Clientid for the relatively rare cases when you need to work with all orders for a given client.