Books - "The Six Skills" and "Staying Alive". Both by Steve Lewis.
"The Tao of Survival Underwater" - Tom Mount
"Scuba: A Practical Guide to Advanced Level Training" - By me, James Lapenta
"Technical Diving- An Introduction" and "Deco for Divers" - Both by Mark Powell
"Deep Into Deco" - Asser Salama
"The Technical Diving Handbook" - Gary Gentile
These will do for a start. Though my book is not specifically geared towards tech divers I've been told it provides a good foundation and introduction to things like gas management, gear selection, what you should have gotten out of your AOW class (one of my students called my AOW class an Intro to Tech on steroids) and why you should take rescue before any other training after open water. I don't know about that but there are things in my AOW that aren't even in many Intro to Tech classes.
I'd also strongly suggest picking up copies of what some generally don't think of as text or information books. They are more on the lines of non-fiction novels but I have found that if you actually read them and look for the lessons, they are there. How people came to make the decisions they did and the consequences of those decisions. Most fatalities got their start long before people even got in the water. And it some cases the paths they took years before led to the thing that killed them. Fatal Depth, The Last Dive, Deep Descent, and Death in Number Two Shaft are some to start with.
I also highly recommend "The Aquanaut" by Rick Stanton (He led the Thai Cave Rescue)
I would not count on a DM class increasing your situational awareness unless it's an exceptional one. A technical DM class might because it's focused on supporting technical and expedition divers but the run of the mill recreational DM class? Nah. A good rescue class on the other hand will fundamentally alter your diving and boost your situational awareness. You say your club churns out DM's. That's not necessarily a good thing.
I would also get the books for Intro if you can. e-learning is ok but you can't make notes on the computer screen that you can pull out of your bag when you don't have access to power and refer to them. I have books for all my classes and all of my students get hard copies. A good instructor is going to provide a lot of info that would be handy to note in the margin of your text book. Info that is not in the book and comes from experience.
Also take every opportunity you can to increase your buoyancy and trim skills, and your buddy and buddy communication skills. Work on disciplining yourself to plan dives and stick to those plans. I use a gold bar scenario. I tell my students to imagine we are on a wreck and have a plan with a max depth of 180 ft. Swimming over an opening you look down and see a gold bar 10 feet below, what do you do? Those who answer drop down quick and grab it, fail the question. The correct answer is to note the position and plan a subsequent dive for it. That's the kind of discipline you need for tech diving in the beginning.
A good Intro class will also start with all the ways you can die doing tech diving. Some agencies actually expect the instructor to discourage those who they feel are not ready from starting down the tech path. I start all my classes with a discussion on how diving can kill you and what we are going to do to reduce the risk of that happening.
