A JTM45 (and most other old Marshall amps) have what's known as a
Capacitor Input Filter for cleaning up the rectified output of the power supply. That is, the raw DC electricity from the GZ34 tube, or Diodes in a solid state version, first flows through a large Electrolytic Capacitor, then the Choke; and finally a second Capacitor. A Capacitor Input Filter is used when the current needed is relatively low; in say a JTM45 thats 450 volts at maybe 150ma. maximum. In addition, a Capacitor Input Filter allows for a smaller Power Transformer than if another type of input filter, called a
Choke Input Filter, was used. (In a Choke Input Filter, the raw DC flows first through a Choke and then the Capacitor)
The Capacitor functions in the filter to smooth the Voltage variations, and the Choke smooths the Current.
To answer your question, in a JTM45 the 32uf electrolytic capacitor is doing most of the work cleaning up the DC.
The Impedance of the Choke (Henries) is more of a critical factor since its resistance is just part of the total Load resistance that the power supply "sees", and for KT66 tubes or similar, it's in the many thousands of Ohms. The goal in power supply filter design is to get the smallest amount of Voltage Ripple (variation) as is practical with smallest practical components (i.e. bigger or more = more $$$).
There are standard formulas & charts for calculating these things. Below is a chart I lifted from the Radiotron Designers Handbook which goes into the subject much deeper. The chart illustrates the relationships between Capacitance & Inductance & Load Resistance vs. percentage of output Voltage Ripple.