I'm also going to be using the full bio-bizz line up for my first grow this year, i've bought 50L bags of both light-mix & all-mix, going to do abit of testing to see for myself...
I think starting your seedlings with light-mix then transplanting to a pot with all-mix once there more developed would be the best thing to do.
If you can only get hold of one or the other i guess the all-mix would be most beneficitial overtime, goodluck on your grow mate!