Help please.. I can't remember if lighter colors go on top or bottom?

I would put the light color at the top, but that's more from personal preference that design capability. A room with a lot of windows seems larger so it seems to make sense that a light color room would seem lighter than a darker color.

Light colors on top and white ceilings make a room look bigger.

Like Diane said

It is really a matter of preference whether the light color goes on the bottom or the top part of the room. However, since you want to make the room look larger, I would suggest you paint the top part light and let the darker color ground the room. That way the lighter color will draw the eye up.

i find that dark on top makes the room feel top heavy and out of balance...

Paint the top part of the room the lighter color, then carry that color onto the ceiling. I've seen this done lots of times on the "flip" shows. It really looks smart.

Oh yes you can paint popcorn, I painted my living room, bedroom and kitchen before I removed it from my kitchen. It makes the ceiling look so much better. As for you Dad, talk to him or just do it. Easier to ask forgiveness than permission!!

Dark colours wil make your room smaller and "eat" the light. On ceilling, you'll seem to be like in a cave ith small high. Light colours reflect light and make the room bigger. You can use dark colours in small room, but only on small touch... generally, dark collors are bette in the lower position...

Light on the top to enhance the size and darker on the bottom to ground the room, one third of the wall height.

FYI: My bedroom walls are dark gray on the top with white wainscoating on the bottom. All doors. trim and ceiling are white and have wood laminate flooring. This is a rental and was painted before I moved in. Was surprised that I actually liked it. Purchased light gray and white bedding and added light coral accents. And about ceilings. Last week I read an article that said satin paint is best for ceilings as it reflects the light. I suppose it would reflect light from a popcorn ceiling even if it's just a little...I'm thinking you should try it .

If you put a chair rail "border" on wall you can have a nice white and your favorite color above. See examples: