Personally, I think something like 5w is more appropriate for a small garden lamp that is normally solar powered and considering the dim light.

Consider, too, that the vanilla Standing Lamp only uses 30w. Well, it used to require 75w. But, a little over a year ago (July 2020), Tynan reduced it to 30w. Should a garden lamp really use a full third of the power of a regular household light?

Besides, I see a number of players using mods to reduce the power consumption of vanilla lights even further - mods like Energy-saving Lamps (10w for Standing lamp) or LED Technology (8w for regular lights).