So i have figured out from these posts I will use one size need 20-21 gauge to draw and already have a smaller needle in the vial to vent gases. When using a filter I willl remove the needle attach filter attach a new needle and then filter it into the vial. On the next packet I will remove the filter and redraw using the same needle as the first packet and then again reatach the filter and use a new needle. How many mL can a .22 filter do and is it necessary to get .22 over .4 Also I have to add the BA myself correct? after the vial is already full if this is correct I believe I read that its 2% of volume so 10cc will be .2ml. How does this sound