We study the important for the experiment features of the effect of the electron shell on α decay in the adiabatic approach. The effect is of tenths of a percent or less in magnitude, depending on the transition energy and the atomic number. On the other hand, we show the predominant role of the inner shells: more than 80 % of the effect are due to the 1s electrons. This fact is crucial for the experiment, allowing one to perform measurements in the same storage rings, comparing for example, the probability of decay in the bare nuclei and Helium-like ions. The analysis is presented concerning the reasons for the relative success and the limits of applicability of the model of "frozen" electron shell used to calculate the effect for more than half a century.