You can use either #47 or #44 incandescent bulbs. Originally they were #44, but many people replace them with #47 because they run cooler and less strain on your power supply and wiring connectors.

The game originally would have had #44 incandescent bulbs.

Here is a link to a ten pack of #44 and yes #47 will work as well. Either is also available in 100 packs for around $10.

https://www.pinballlife.com/44-bulbs-box-of-10.html

You can Undrain a post, it will appear as a drained post, click on it and choose to undrain it.

If you're in a hurry, check your local auto parts store. Some carry #44 or #47 bulbs, but be warned, they will cost more than from a pinball supplier. If you can wait a few days, order online from The Pinball Resource, Marco Specialties, or Pinball Life....to name a few. Or Google #44 bulb and you will find many places that sell them, including Amazon. Order a box or two containing 10 bulbs. Price for the box is around $1.50. You will use them as replacing burned out bulbs is routine maintenance.

I recommend switching the GI bulbs, especially in the backbox, to LEDs. They run cooler and put less strain on the rectifier board. Comet pinball is my goto place for LED replacement bulbs.