McImes, the good news is that the masterclass is free, and anyone can sign up. The bad news is that you need to enroll for your whole life, and the further along you progress, you actually don't feel any closer to being finished....
Jesting aside, I agree with Zach in that it's best to tune into what's immediately happening in front of your bow, especially in the early stages of learning. As you improve, and your responses to what's happening right near the boat become automatic, you can open up your conscious horizon a bit, and look around a bit further out in front to take advantage of patterns that require bigger inputs to dial into.
It sounds like you're doing out and backs fairly close to shore dealing with sets of groundswell? If so that's pretty different conditions than most people are getting out in on their downwind runs, and I can't offer much specific advice for your environment. Be wary of putting too much faith in that bathymetry theory, I have certainly been caught inside and snuffed out by the 8th or 10th wave at places like Black's or Laniakea, ha ha, I wish those sets had read up on the matter and learned they are supposed to group up in sixes!
So much of downwind is unconscious pattern recognition, I think it's hard for experts to remember what it was like being a noob, and so advice is handed down like Deano's "just put the nose in the hole" which is both correct, and also a vast oversimplification.
It sounds like you're already at the point where you are putting together long sequences, but then every now and then you totally lose your speed? Maybe take a step back and try to maintain a lower intensity level and link up waves that are a bit smaller/slower than what you are capable of. Then, if you find yourself heading into a dead end, look around and find something nearby that you can reach if you go max out for a short time. Basically, try to use your energy reserves to prevent slowing down, rather than using them to pull onto something really fast.
If you want to maximize your average speed for a given run, you need to be going as hard as you can maintain for the whole run, all the while using that effort to stay moving on the fastest wave energy that your effort level allows you to catch and link. So if you are making perfect decisions and have perfect boat control, you can link faster wave patterns. An expert can go max sustainable effort the whole time because they aren't making mistakes. As a beginner, you have to leave yourself a "cushion" of power reserve for when you make a mistake, so that you can power up and paddle over a wave or whatever to get back into the pattern.
You mentioned that when you are falling out of a pattern you look to the sides for something else to get onto. I would say this is a good move, and in general if you are not actively linking solid energy, it's best to have your boat at a pretty big angle to the fastest moving swells (you want them hitting you on the beam or quarter, not from straight behind) because when you aren't going fast enough to catch them, those bumps will just slow you down if they hit you from behind, versus if you quarter them or take them on the beam, they pass under without molesting your trim and flooding the cockpit, etc so it's easier to keep your speed up.
Get in a double with an expert if can. I haven't done this with a real master, but even going with my peers I have learned a lot in seeing how they deal with situations a bit differently than I would have.
Good luck, I look forward to the post-class debriefing when we are all 90 years old in wheelchairs!