In one of the later versions of Makou Reactor, 1.6.5, there's a new option there called Field Scale in the walkmesh. Like Kald said, if it's set to half the original value (it's usually 512 by default), then it takes twice as long for the player-controlled group to traverse that field. It doesn't seem to have any effect on groups that are being moved through a script, which is handy.
So what that means is, I can set the game to run at 60fps in a field screen using your Oytugh tool but get a normal rate of movement. I interpolated the field animations for 2x frames as well, and set timings in the reactor (wait, panning, etc.) to about 2x what they originally were and it seemed to work out in the test, give or take a few tweaks here and there to handle special cases (the last few seconds of Cloud & Jessie running out of the Reactor carries them too far into the FMV due to the fps dropping to 15, for instance). I was just curious about how it would look.