Straight forward osc. Mikmo and others suggest using this program to calculate freq and component value. I have not tried it, but you can. I always start with this config.
I do vary the cap value and type.
I like to use an LED to gauge what the signal speed is at any given time or pot position. The signal speed is reduced/slowed by adding the LED, but it is a worth while trade off to me. Usually the faster speed will be enough to crash the toy, so when needed I will add another res between the pot and battery+ to make the toy stable.