So from my limited experience I have the following advice. From everything I've read, you don't want to change the light cycle on these guys. Once your at 24x7 stick to it or else it can play a little with their minds. I started with 20/4 and kept it there the whole grow on my lowryders.
As for transplanting. I read somewhere to transplant when dry and then water immediately as it cuts down on shock. Its what I've done for 3 grows and it has worked great.
And on to the nutes question. I had a hard time finding any info on when to change it up for auto flowering plants. From what I remember I started slowly adding flowering nutes when they started showing sex. Mind you, I started slow so as not to over nute them, but thats when I started. I only have 3 grows under my belt so take it for what its worth.
On a side note, I'm looking forward to see what this led thing does for you. I love auto flowering plants and to be honest they were my favorite so far. They reward you with crazy fast growth, easy lighting setup, and my lowryders had a great smoke. I have been interested in LED's and might want to go with them for a mother setup I want to start. I'm subscribed!