re: perpetual grows
that is a terrific question and you won't find a lot of threads answering it
...and i don't know for sure, it will be interesting to see the responses
i have read that there is a limit and it is around 20 times...the reason given in the post i read was cell division
just like all life, a cell can only divide so many times in a healthy way
re: clone from a flowering plant
yes, you can clone from a flowering plant
try 24&0 till it stops flowering - maybe 2 weeks or so
then switch to 18&6