Welcome back! It's very good to see you in these threads again.
Alas, I don't know enough about chaos theory to intelligently evaluate your idea of a boundry. (Doctor Stochastic does, so I'm pinging him.) Even if the math makes sense (which I don't know) it needs to be tested, or at least supported by some unambiguous observations.
The notion of a gradual (and sometimes not-so-gradual), step-by-step series of changes in a population, which over time accumulate to become "macro" evolution (or really, just speciation) is difficult for me to imagine being interrupted "just in time" to prevent things from "going too far." But science always follows the evidence, so I'm willing to follow reality wherever it leads.
I must say, however, that you are the very first person to even suggest a possible mechanism to block "macro" evolution from taking place. That is confirmation of my long-held opinion that you are one of the best people on your side of the issue.
I already posted something suggesting that mutation likes like a random walk. There are no intrinsic scales for random walks. Structures arise of all sized. For evolutionary theory, these structures not only extend over space, but over time. The example of the convection cells (in hot oil for example) show that seemingly regular structures arise merely by the input of energy. Such structures (from molten rock) can be seen frozen at the Devil's Postpile (California) and the Giant's Causway (Northern Ireland). I've seen both; they look like hexagonal bathroom tile laid out inexactly.
There's no evidence that evolutionary processes are linear. Selection is quite arbitrary. Mutation may have non-linear consequences also.