The US test standard (MIL-PRF-19978) calls for 1 hour charge, 10 seconds discharge and than looking for the voltage after 15 min (or the maximum if reached earlier in a more leaky capacitor). The difference to the GOST is about a factor of 2-3 in the time scale and a longer charge time at the beginning.

For many capacitors DA tends to go up with the longer time scale and the longer charge time at the start also gives slight higher DA numbers, though not much.

The faster russian test procedure is slightly more convenient, as it does not need input impedance of the meter as high.

With very low absorption it is a good idea to connect the voltmeter only after discharging the capacitor. Otherwise one would include also dielectric absorbtion of the input capacitance of the voltmeter. So there should ideally be a switch (relais) at the voltmeter input. With a slightly different configuration one can use a single switch to short the meters input and do the charging / discharging at the other side of the capacitor.

One can see the effect of the length of the discharge phase, by using a short discharge and record the data from the start. Except for very high DA caps the recovered voltage just add up. So instead of a longer discharge, one can use the voltage at that time as the new "zero". So the information for a longer discharge time is already in the curve.

In this repect the US way with a long charge time is more universal. With a long charge time a single measured curve could cover different time scales in a single test.