tripod, geared head, star tracker on geared head and then ballhead atop the whole thing. set the camera on ballhead, install lens warmer and focus with bahtinov mask and insert dummy battery to the camera for power. start shooting from bottom left, five images at 44s each. repeat until the area you want to shoot is covered (four, five rows I think). shut down the tracker and take same images for the foreground, re-fcous if needed. put the lens cap on and let the the camera take couple dozen dark frames while you pack your stuff. at home, don't forget to take some flat field images. calibrate, stack, stitch the images.
85mm is good balance between light gathering and resolution and image count. I shot at f/2 because the Samyang isn't so hot wide open but there is still over 40mm of free aperture available and the vignetting isn't as pronounced.