Hi All newbie needs help with 1st Orchidarium

[Jewel Orchid Man]

I’m getting ready to build my first Orchidarium and have a couple questions. It’s only 24x12x18 with screen top. I'm using a cork background, waterfall, fluorescent lights and 2 CPU fans for airflow. Now it’s time to put it together. Should I use silicone around the entire perimeter of the background to attach or in just a few spots? Also I’m not sure whether to make the waterfall drip down the background or a rock stream or something. The big question is the plants. I grow a lot of jewel orchids so my environment must be safe for them, fungus and spider mites are potentially catastrophic. My Orchidarium will be 70-80 temp and 75-80% humidity. Can anyone recommend any orchids that are small and can grow in my enviornment? I’m good with the jewels but a total rookie with regular orchids. I really want to make a dense tropical Orchidarium but want my Jewel Orchids to be an important part. If anyone can offer some suggestions I would be grateful!!!