fwiw, i started out with an aga-t2 and put it on top of a vamo, just to see what gennie's are all about. even with a 'higher' resistance coil (1.5-2 ohms) on a regulated mod, you'll still get enough of the genesis experience to be able to decide whether or not you want to invest more money into it.
basically, i'd say just start with the rsst and save the mech mod for later. if you can deal with building it and like the way it vapes, then you can buy a mech mod later (and know that it will just get better and easier from there). if you don't like it (some people don't, for many different reasons), then at least you figured it out cheaply.
that being said, it's a WHOLE lot easier building a gennie with a mesh wick if you can oxidize the wick with the pulse method, which isn't possible with a regulated mod...