Digital BW, The Print

I have just bought MIS spongeless carts for my 1160. Some things are
not quite clear yet, hope you will help me out:

1. Does the MIS Bottom Fill Adapter only have to be used the FIRST
time you fill a cart? Or every time? My guess would be only the first
time, to remove initial air pockets. That is, if you can leave the
carts inside the printer when refilling? Or do you have to take them
out each time? If so, why?

2. How do you know when to refill which compartiment in the color
cart? Or do you have to refill all three every time the
out-of-ink-light goes on?

Thanks!

I g o r