Hi,
there is no setting to cover all things you want, I guess.
First of all what Manish wrote is right, you should check the strategy on the storage type. Does FIFO make any sense on a fixed bin storage type where you can have more then one fixed bin? Probably not. Because when you do replenishment before the bin is empty, you will probably have the oldest date always in the same bin. Well, you could change the setting so that always the newer date is taken into the quant, then FIFO might be usefull.
For your requirement you could think about to use the available quantity as sort criteria. So when you sort, the bin with the highest quantity comes first, then the 8 pcs are taken from there. But what happens if you need 4 pcs? You want then the system to go to door bin 2? - whoops, doesn't work. You will always pick from the bin with the hightest quantity. If you want a "best fit" strategy - you gotta build it.
Brgds
Juergen