Have you had a look at TVDAs before? there is one even here, on the Exchage.
You can find more on se.com
From my experience - to learn M17x the best idea ever is to ask localy a SE HVAC guy to show you. If you are lucky there could ba e proper training available too. (yes, try to catch a sales rep to hook you up!!)
Otherwise it is a very steep learning curve.
M221 or M241/M251 are by far more user friendly.
M17x are for truely specific development. Too many ways to go wrong.
Best of luck !!!