The old air cell batteries were about 2 volts. Your tubes are all 2 volt tubes so 2 volts for the A battery would be right. The C voltage can be experimented with, it will be low, I would guess 4 volts or lower. This is usually not critical and varying the voltage while checking performance will find the right voltage.
A LM 317 based power supply could be made, one was listed on this forum as a farm Radio Power Supply.
Ed.