That is a great article and if you look through his website, he has a lot of really helpful articles.
Making timed descents and ascents, as he suggests, will be very helpful before the course. You'll be stopping at 10 feet, 20 feet, and 30 feet, and then the reverse coming back up, holding very steady at each depth. Then start working on the timing and making it smooth. During the course they'll start to task load you (S-drill, SMB deployment) during that timed descent/ascent, so it will need to be almost like second nature to be able to hold your stops.
There are lots of mentors in the GUE community in and around various parts of NY state, especially around the St Lawrence river, from what I've seen. Good luck!