Get an Altek Lamp driver board from Cointaker now... You can use the current pinside 20% discount Melissa has going on.
The buy all you LEDS at the same time for the same discount... You do not need fancy ghostbuster non-strobing bulbs as Bally of that era do not use lamp matrix's. Simple cheap LEDS work. Color match them to your inserts, use warm white for your GI. After that it's all just tweaking and playing. I lot of folks like to use blue LED's for GI on a Xenon.
Do a youtube search for XENON and LED and you should get a hit or two to help you decide.