Look for a very bright festoon that has lots of LEDs on it to get the maximum amount of light and that directs the light into the glovebox. You don't need to be concerned with how wide the festoon is since you won't be fitting it into a possibly restrictive fixture. I used one of these:
https://www.ebay.com/itm/2-x-36mm-1-...72.m2749.l2649