Hope fig friends can share their experience regarding what size bag is appropriate to have.
I Would like to get some bags. What is the best size to have 3"x4" or 4"x6". I am thinking of
getting more 3"x4" but uncertain whether they are too small. I would like to use them on my
Florea, Salem Dark, Ginoso & RdB's.

P,
I use green dyed 4x6 inch.

ditto to what Michael said.  

You can't put a 2x3 inch bag on a large fig.

Thanks. I will get both 3"x4" and 4"x6" bags.

The other question is I am thinking of putting the bags on at least 3 weeks before they start to ripen to beat the fruit flies - would that be sufficient time to prevent them from laying eggs.

4x6. Best thing is dollar store by me had them. 8 bags for $1

I don't have fruit fly issues here. I have wasps, ants and yellow jackets along with squirrels (I have already shot 6 this year). I put the bags on just before the figs ripen.

I've been using organza bags for a while now, and found that it keeps the figs wet, now I'm trying the little berry box (the clear plastic ones) it seems to hold the fig dryer, will see soon.

I bag mine in 4x6 as soon as the figs are fingertip size. My LSU Gold and Siblawi breba will have to be cut out of the bags.  

vito,
I don't have issues with moisture and the bags but I do seem to bag my stuff later then others. I have only tried those berry boxes a few times and they seemed to add heat to  the fig which may or may not be a good thing. I hope you'll update us with your results.Also I have never had substantial bird issues as I use about every trick there is to keep them away.

Nothing really bothers my figs (i have too much other stuff for the birds to eat!), but I do start to bag as soon as the color changes or they start to droop.

Make sure if you order from ebay that you double check the size.  I ordered 5x7 and got teeny tiny bags...they were 5x7 centimeters, not inches.  Grr!

Hah i did the same thing. $4 shipped for 100 should have been a red flag

I found that 5 x 7 was easier to install.

I started with 4x6 and as you can see in the pic below they were too small for my almost ripe figs.  Now using 6x8, they fit easily and I see no downside to having extra room.
 

Yep, I do need 5x7 for my Lemon and Texas Blue Giant. Use 4x6 for others.

Going by your picture, it doesn't look like you put it on properly.
4X6's fit mine well.

If the gloves don't fit you have to acquit.

5x7 INCH is perfect