"were to get the bulbs"
Favourite source in the States seems to be here
Not 'bulbs' but LEDs, use about half the current or less than the 'grain of wheat' filament bulbs in the Graupner originals.
I haven't seen those since I used them for bow and stern jack staffs on my 1/72 destroyer some 30 years ago. Mine came mounted on a long brass tube, ideal for fixing on the model 😉
At 1/25 you can probably fit 3mm or even 5mm LEDs to them.
Have fun, but don't get all lit up!
Cheers, Doug 😎