Hi, I have just looked at your excellent video about using DSLR Dashboard
lrtimelapse.com/gear/dslrdashboard/
You are saying after about 7 sec "I recommend to leave 2 or 3 seconds dark time inbetween the longest shutter and the interval..."

Does that mean you have to have 2-3 seconds between each and every shot in the timelapse?
When i use my Nikon (have not tried the dslr dashboard), i have just 1 second between each shot, so a 6 sec exposure gives and interval of 7 seconds.

The "dark time" is needed to transfer the preview to the tablet, evalute it and be able to control the camera. If you set it too short (for example 6 sec. exp, 7 sec. interval), qDslrDashboard will not be able to control the camera anymore.
You should try with your setup whats the shortest "dark time" you can use.