I have had a Black Soldier Fly contain for about 3 years now. I found the Black Soldier Fly Larvae by accident, and raise them for fun and to sell to a few friends who feed them to their chickens. Well something about my set up, about everybody's set up, has always bothered me - it's the ramps the BSF use to self harvest. These ramps are such a pain to set up and hard for the BSF to find and use.
You can look at my old set up here. It's a 55 gallon water drum with a door cut in the side. I used PVC pipes for ramps that ended in collection buckets. Although the system worked, I always felt the chances of the BFS larvae finding the ramp and using it were not as good as they could be. A broad ramp leading to a broad exit hole would be better, but you can't just insert a plywood ramp into your set up. First of all it will rot, and second of all, BSF can get through any crack and they will all end up lost on the other side of the ramp. Then I thought one day, why bother with a separate ramp? Why not tilt the whole container the 20 degrees I wanted and cut a long slit for an exit hole in the side?