BlackVue is officially now shipping the DR650 series with either a 16, 32, 64, or 128GB micro SD card so you should not have any issues using a high quality 64 or 128GB card (although you should make sure you have the latest firmware installed).
If you connect the yellow (hot) to the brake and the red (ACC) to the radio/cig lighter, then the switch on the Power Magic Pro should work perfectly. Just be sure to use a test light to verify which fuses are actually hot and ACC.