Approach to 8 channel bit banging
If changes of the values are rare (relative to the running of the LED update protocol) the second approach is clearly lighter on the CPU (and hence results in faster communication).

You might want to google for "vertical counters", which uses a similar approach to spread the bits of a number of counters 'vertically' over a number of bytes, with the aim of making a fast set of counters. I think I first heared of this from http://www.dattalo.com/technical/software/pic/vertcnt.html