Downwind, all of the above. There are of course several sources to use including the QRH, Vol 1 PD and FPPM.
The figures all vary with weight, wind component, ISA deviation, and configuration.
They are simply some rules of thumb that I and others may occasionally use.
How about this one ;
Climb 20 min, 1700kg, 120 nm
Descent 20 min, 300 kg, 120 nm
If I have one figure in mind for the SGR of the 700 and 800 I use ;
-700 4.7 kg/nm
-800 5.2 kg/nm
Wind correction to these two figures use;
40kt T/W x CRZ by 0.95 (80kts x 0.90)
40kt H/W x CRZ by 1.07 (80kts x 1.16)
I can apply this quick and easy check to our company flight plans and find the fuel figures I calculate are usually VERY close to the company produced flight plan burn figures. If not, why ???