I removed the ugly hot melt glue and replaced it with eproxy putty. I might paint it back later.
I tried to compare the focusing chip which utilizes the phrase detector, with the live view and the result is consistently effective and accurate.
And then I set it up on the Sky Adventurer, and it supports well, and the counter weight is far more than enough. Both the internal RA motor slews well, and my DIY DEC motor works well, too.
You can also see the Polemaster above.
Really want to try it out under than stars. I have several prime lenses, a 8mm fisheye lens, a 50mm f1.8, a 200mm f2.8 plus this 300mm f2.8, and that should be enough for quite many targets.