I have grown regular luffa for a zucchini substitute and it seems to love full sun. Mine grows over a cattle panel trellis arch and the south side vines tend to be more fruitful over time.

I'm going to try growing it up and over the south-facing wall, so it grows down the other side or across the top on wires. Not sure exactly how I'm going to work it, but I think if I can get it going, I can make it work. Unfortunately, I don't really have enough room for a cattle panel trellis, although I'd love to have one. I think it's safe to grow outside the wall, because not many people will know what it is, and if they ask, I'll tell them it's inedible. Not many people grow it as a food, mostly for sponges.

One of my neighbors loved seeing the beautiful blossoms and is planning to grow one on a decorative trellis just for the blooms.