IMO it depends on the student when they are ready. surely you are not ready to go tech with your dives being avg of 30 ft. I say this because you have not experienced things like the increased gas usage at depth. you have not experienced the lack of a monster at 61 ft. that sounds funny but it is true. there is a confidence factor that only comes from experience. courage you get from your instructor but confidence is from experiencing things your self. there are things that may take a year or so for the light to finally come on and make sense. my wife for instance made a dive at vortex to the cave enterance. she was scared to decend into the drop hole. and surprised when nothing happened to her at 60 ft and then even more when on shore found she had little air. she said this never happened before. I said you have never been deeper than 25 - 30 feet before. how can you appreciate the idea of rock bottom with out that experience to reinforce teh need for such a calculation. classroom theory has to be second nature. forget the names of boyle and the others, just know the meat of the matter.... you I am sure found that shooting a buoy from 30 ft is no easy chore as compared to 60 ft. just one of those things you have to experience and figure out why. the more you figure out through experience the safer and more confident you become. for me, my tech class was easy. calculating partial pressure was native because of my OW class in the 60's and occupational background,, so was e a d when i took my nitrox in 2003. seemed stupid the way they did it but the light came on in tech class using trimix....... e a d and e n d are very similar if not down right identical. same process just applied a little different. no more do you calculate e a d in nitrox class because computers do it for you. With out going through it you have no idea of why you do e n d the way you do. classes have been dumbed down and it leaves the good stuff to be found on your own like e n d without ever knowing e a d. another course is rescue. take the class and by theory you never have to use it to save a life. the real meat of the class is the aspect of how to prevent the situation and monitoring your buddy and surroundings. I cant say if you are ready for tech or when. You appear to have a rational scientific and logical mind. if so you should be ready much earlier than most others.