I have started on the machine and as yourself, I'm looking to improve my batting as I'm primarily a bowler and a pinch hitter. Looking to bat a lot straighter and similarly improve playing balls down the leg and on the pads.
On my third session and having changed my grip slightly, standing straight with slight bend in the knees and keeping my head straight, I have seen an improvement in playing straighter as well as gaining confidence
I started at 60mph this week and after about 10 - 12 balls, I got my eye in and timed it better.
Not for everyone but a few videos on YouTube regarding stance helped me and practicing this in front of a mirror at home.
I practice my stance and simulating a drive in front of the mirror to see if I'm playing it correctly or not.
Head movement first is vital.
All the best with the winter session bud