Where on that site is a schematic so we can tell what we are dealing with, as I said a link would be good.
Where are you getting this information about 70V being the minimum you can get from the driver, it is not what the 74141 gives.
Do you understand the fundamentals of neon lamps?
They have a strike voltage that turns on the discharge. Once on there is very little voltage dropped across it way smaller than 70V. The only way to turn it off is to reduce the current to a point lower than a critical value. This is normally done by reducing the voltage to zero, or by having a seriese resistor in the order of several meg ohms.
Small neon lamps can make very good audio oscillators using a 2M resistor feeding the lamp with a 0.1uF capacitor across the lamp.