Oh come on. It doesn't look precariously perched at all!
I have confirmed that once the brass reducer is removed it's a standard 3/8" thread. I've got it mounted to the TB-20.
Does it make any difference that this thing can take advantage of mirror lockup? It has settings to activate the mirror lockup and allows you to configure how long between mirror up and the shutter being activated.
I guess the only way to know is going to be to try it out. The shoot I am planning is going to be at night. Last year I did a quick and dirty 12 frame pano from the balcony we were on (http://tinyurl.com/bkbs8s3). Exposure was 3s/f8, ISO 200. I will probably bump ISO up to reduce exposure time (mainly to reduce total panorama time) as I am planning between 100-150 photos.
I could try to pick another nighttime spot and try shooting it with the current setup (D3 with 70-200@200mm on Gigapan Epic Pro on top of TB20 mounted on GT2530) and see what I get.
I've got a month before the Dec 9 shoot so there's time.