Shift register question.

For My roof led project, I am using 8 shift registers (74hc299) along with 8 uln2803's (to provide the 20mA/led).

I am working on making an easy way to control different patterns with a microcontroller. I'm planning on using some multiplexers connected to the Data in. Now here is my question:

Can I just use a 8:1 mux (I think it is a mux, 8 inputs, 1 output) and have the output connected to the shift left and Shift right inputs? (see picture). Then I can control which way the bits are shifted using the So and S1 on the 74hc299.

I would handle all the pattern generation in the micro. The shift registers should be fast enough that you can just shift in each new state with the Ouput enables off and then enable output when the data has finished shifting in. Even at 10KHz you should be able to load over 150 data sets per second - way faster than the eye can register. This would simplify your hardware design - you would only need to shift one way - and make the number of patterns you can generate limited only to memory size or what you can calculate.

I was also considering that as an option, but I have absolutly no microcontroller experience, so I figure I may as well simplify some things in my hardware to save on the coding.

Also, I will have this circuit kinda on display in my trunk, so it'll look more impressive if I have a bigger circuit.