The mechanomeric selective enzymes and other mechanomers will themselves be mechanomerically selected, in what is called here "early mechanomeric selection":
Replication being a more complex function than and indeed including polymerization, replicases must be more complex and therefore occur more rarely in random mechanomer stocks than polymerases, but cross-class replicase pairs, one from each of two mechanomer classes replicating mechanomers of the other, will evolve in what is called here "mechanomerogenesis" (analogous to abiogenesis), in which random mechanomers and monomers of both classes are mixed, and such replicases upon encountering one another engage in a more or less exponential course of mutual replication (with a more or less exponentially-increasing heat of replication), with the first such event and pair likely taking over the system. Many such events will produce same-class pairs, which pairs will also limit mechanomeric evolutionary system sizes, and many cross-class replicases produced will be incapable of replicating mechanomers incorporating monomers of all the kinds of the appropriate class supplied, and more or less inaccurate or fuzzy in their replication of the mechanomers they can replicate (such reduced-monomer-set replicases will often be workable until better ones are developed, and such fuzzy replicases will be useful for increasing the incidence of well-conformed mechanomers in random mechanomer stocks).
Once a workable replicase pair is developed, at least one polymerase of each class polymerizing monomers of the other will be developed by matricial mechanomeric selection, using random mechanomers synthesized by purely-chemical (non-enzyme-catalyzed) polymerization and then replicated. Such polymerase pairs must operate in the same directions as their classmate replicases, although replicases and polymerases operating in both directions will be developed to mechanomerically select mechanomers which in the course of synthesis coil in such ways as to bury the ends first synthesized and prevent replication, as well as those which vary in their conformations depending on direction of synthesis.