bogdan666:
only 2 wires to move, so after this the 3rd 595 will be the one driving my rows
But do you understand what I meant when I said the SPI pins? They are particular pins on the Arduino. Which pins depends on which type of Arduino. But they are almost always marked "MOSI" and "SCK". You can't just use any pins. This is because the Arduino has a dedicated circuit on the chip itself which is designed to send data at high speed to chips like the '595, and that circuit is connected to only those pins.