Our local tech instructor teaches iantd and we just got through advanced nitrox and he brought up rec trimix. Started doing some research and here we are lol.
Is he the only tech instructor you know? If yes, I'd consider talking to other instructors and divers who did courses with other instructors. These chats will allow you to compare his standards with others and have a reference to understand how good your instructor really is.
Then, if you decide he is the right fit for you, I also think the rec trimix plus is the best choice.
P.S. f you are interested in caves too, have you thought about pursuing cave training before tech training?