Taxi and Descent fuel requirements

[Emi]

Merry Christmas once more gentleman,

planning my fuel for my flights there are two questions which I could now answer by looking at the manuals.

The first is the taxifuel: Is there any rough value you would use to calculate the fuel for taxi and runup?

The second is the fuel/time/distance requirements for the descent:
It seems to be the Connie does not like the 1/3 rule as it results in a rather steep descent. Is there a certain recommended V/S and IAS for the descent?
What is the fuel consumption in such a descent?
Unfortunately the manuals only contain climb and cruise tables and none for descents.

Thank you for your answers in advance!
Emanuel