When is the best time to take cuttings, how big should they be and how should they be stored?

After leaf fall when the trees go dormant, about 8" or so as long as you have 2 preferably 3 or 4 nodes, in a plastic food storage bag in the fridge, unless you are ready to root. There are obvously other times and ways you asked for the best, that's the best I know. 

I've received dormant cuttings from UC Davis and many are about 12" which I think is too long.  I end up cutting part off.  I experiment with the 2 nodes I cut off to see what happens with different rooting methods.  Barry is right about the size, although sometimes those two noders root too!  8" is safer for sure.

Suzi

There is a ton of info here at the forum on the subject.  I recommend searching for the following terms:

• storing cuttings
• cuttings refrigerator (or cuttings fridge)
• cuttings dormancy
• non-dormant cuttings
• cuttings advice
• cuttings questions

You'll find a lot of info there that people will probably forget when responding here.

You can take cuttings any time and store them in a baggie with a humidity source (a fully wrung out paper towel) in the fridge, or leave the baggie out in a warm spot if you want to root them immediately. 

Most prefer taking during dormancy, but you can take while they have leaves, just clip off the leaf at the stem (leave a stub), bag them up (with humidity source) and come back about a week later, the leaf stem stubs will knock right off - this allows the leaf to separate naturally.

6"-8" is normal.

Also see propagation and rooting tips here: 

http://figs4fun.com/basics_Propagating.html

and

http://figs4fun.com/basics_Rooting.html

This year, for the first time I have had very good luck rooting semi-green, semi-lignified cuttings from my trees.  I filled two liter soda bottles (the bottom half) with damp coconut coir, stuck in a fresh cutting (with all leaves removed except the topmost small leaves near the terminal bud), and then covered the whole shebang with the top half of another soda bottle.  I kept them in bright light/no sun.  All rooted within three-four weeks.  I did this in late-spring,/early-summer so that the newly rooted "trees" would grow through the season.  I also air-layered some stems, and that worked too.

Wish you luck in what ever method(s) that you decide to use to propagate fig trees.  All are fun and very rewarding.

Frank