If you want to use the dosing methods we use here, it'd be best to use the human meters. Besides being much cheaper test strips, our dosing methods were written with human meters, back before pet meters were invented.
Note, the Libre often tends to read lower than a blood glucose meter in low numbers. We suggest double checking with a hand held for numbers under 100.
It's hard to guess what she will do on a 0.25 unit dose, but given how high her numbers are off of insulin, I suspect you'll be OK with 0.25 units. If she still is eating some dry food, we'd even be suggesting 1.0 unit as her starting dose.