The only limitation as such is a minimum of 760kg in each main (wing) tank for ground operations, and cooling of the electric hydraulic pumps.
11000 kg would be across wings and centre tank. From memory the wings hold 9000kg (4500 each). Total fuel is about 15880kg.
Haven't flown 300/400 for about 3 years so not sure what is current regards centre tank fuel pump limitations.
Re Standby Hyd pump, 300 normally powered by Gen Bus #1 and will transfer to Gen Bus 2. NG normal power is Transfer Bus 2
Hope this helps