The argument itself is not difficult. Plate Tectonics is wholly predicated on the assumption that the Earth can't get bigger ("because we don't know how it could / mechanism etc.)
Fatuous bollocks, of precisely the sort we've come to expect from adherents to EE nonsense. Plate tectonics is predicated on the observational evidence, and no such assumption is present. Indeed, it would be almost as fatuous as the drivel you've erected here to make such an assumption, because the observational evidence tells us categorically that the Earth is
getting bigger, just not on remotely the scale for the fuckwittery you propose.
Earth expansion is predicated on the simple geological evidence that it has got bigger by the extents of the ocean floor, absent of any assumptions,
Except, of course, the underlying assumption that expansion occurs. There are no observational data to support the conclusions extant in the EE bollocks, and the geological evidence you cite is wholly supportive of PT.
and acknowledging that there is a big question hanging over how energy is transformed into mass (which is one for physics),
That question has already bee answered by physics, and your phrasing of the question only demonstrates your abject ignorance of said physics, not least because energy isn't transformed into mass, energy is
how that mass is transmuted into matter (which is one for physics and geochemistry)
Again, already answered by physics, through gravity ad the electromagnetic force. No mysteries there.
and how that material transmutation ends up as mantle material + water (which is the big question for geology).
Already answered; see above.
I think there are already reasonable bounds within which energy mass and material can be logically linked,
Already dealt with. It does amuse me that every single proponent of this thought-free cock demonstrates such a paucity of understanding of basic physical principles.
e.g., it could be argued to be Moon capture or "collision with the Mars-sized object" (= origin of the Earth-Moon sytem back in the Proterozoic). According to stratigraphy and structure Earth expansion is already a lay-down misere. The big question is the geochemistry one.
Red herring, and still not dealing with those fatal conservation laws. Any of you going to get to those any time soon?