You’ll lose a bit of accuracy at the lower end, otherwise they will work well enough.
I’ve written it here a few times, all you need is to add a wire-ended 27 Ω resistor in parallel with R18, the 120 Ω resistor (“1200” printed on it) that’s immediately behind the CT4 input socket of the emonTx (bottom left here):
There are holes ready for it. The resistor need not be any bigger than 0.1 W, though 0.25 W or 0.3 W will probably fit (the holes are 8 mm pitch) and be easier to obtain. That will make CT4 input the same as the other 3. You’ll need to change the calibration in the sketch to make it the same too.
It might pay to calculate your maximum current - it won’t necessarily be the 200 A that the wiring is capable of. See US 200 Amp Service explained or Do I need a 200 Amp CT?
You might need to change the same resistor on the inputs you use for the 200 A c.t’s, I can tell you when you decide which you’re going to use. And the calibration for those must change likewise. You can do that with a programmer and the Arduino IDE (or any serial terminal emulator).