@Jason-Gong, I can't find full datasheet about NS107S and information about latency. First, I think the latency of Data and Clock lines are not aligned and it's different. Second, why you think 24MHz is not too much for these? In the datasheet of wrote: "Oscillator Frequency: 30MHz" but what does it mean? I think you should decrease frequency if it's imperceptibly for eye. Next you can use SPI de-multiplexing for more parallel channels. It's not easy way but stable.