Can I use 3 watt led bulbs?
You can use 3 watt led bulbs, but you should make sure the base is an E26.
Does anyone know if you can buy different lampshades to fit this lamp?
It’s adjustable as any other lamp but I believe they look better with the original ones
Does this lamp turns on/off using wall switch?
Yes if the wall outlet is attached to the wall switch. Plug in the lamp, turn it on. If the outlet is attached to the wall switch try to turn it off at the wall switch. If the lamp goes off you have your answer. Just leave the lamp turned on all the time but turn it on or off with the wall switch.
How tall is this lamp? How about the spacing of each layer?
It is 63 inches tall，and the spacing between each layer is 16inches. In addition, the shelf is made of high-density board and it can hold up to 65 pounds.