The IANTD "Technical Diver" and "Normoxic Trimix" courses use the "IANTD technical diving encyclopedia" as a text. The test was a mess when I last saw it but you can get by that. I prefer it over the PADI/DSAT texts. DSAT has its moments though...like the bit about having some one hold you down or holding onto something with your legs while you deploy a bag. Holding onto a blown up bag is dangerous, stupid and unnecessary...IMO, of course.
ok, a few things that I specifically like about the IANTD text over the DSAT. The IANTD texts contain exerpts from and references too lots of studies on things like narcosis and the phisiological effects of deep diving and different gasses. It contains lots of phisiology period. Maybe a little more in depth than needed but better too much that too little as far as I'm concerned. The DSAT text has little or none and I don't think that's appropriate at this level of diving. The IANTD text contains what I think is a pretty good section on equipment configurations and evaluating your own. DSAT is pretty rigid and I don't recall much else being discussed...and for goodness sake don't use a reel to hold down your long hose. The IANTD text contains a lot of decompression theory and talks about different models while DSAT just sticks you with their software and a computer. The IANTD text also devotes some space to technique which is rather THIN in the DSAT materials. I don't like the way either text addresses gas matching. The IANTD text uses some screwy method based on sac/RMV which isn't dependable as far as I'm concerned and DSAT hoses it up too. Just do it the way the cave agencies teach it and you'll be in sinc with the rest of the world! Not that being in sinc is always good but in this case I think it is. There are other points but that's a start. I'm sure that if I went back and looked at both texts again, I could come up with a lot more but it's been a while.
The courses...
IANTD gives you the option of combining the tech diver course with normoxic trimix. In fact you can combine advanced nitrox with advanced recreational trimix. By taking advantage of those options you can do this without doing any deep diving on air. Arguements on the virtues (or lack of them) of deep air diving aside, DSAT, as far as I know, doesn't give you any way out of it. IMO, you shouldn't have to dive to 170 on air (165 in the case of DSAT) to qualify for trimix. From what I understand, some are teaching the DSAT course with "simulated" deep dives and that it's condoned! If I were you I'd at least double check with your instructor to make sure you're going to do real dives.