So I'm having issues with lines in my test prints, and I believe it has to do with air in the sponge/printhead. While researching this topic, I saw a post by Hendo that said "If you have to do anything to the cartridge after filling it, it does not work." This is upsetting, because that rarely happens for me, especially with color. First of all, do you agree with that?

So I'm not sure exactly why I'm getting air in the cartridges, and not sure how to get it out properly. Here is my procedure for HP #97's:
1) Put cartridges in warming pan with (SEE THIS) yellow for an hour, soaking the printheads.
2) I fill 3ml of (SEE THIS) yellow in each chamber with heated (clean) (SEE THIS) yellow
3) I spin them printhead out for 5 minutes @ 3,000 RPM
4) I spin them cap out for 5 minutes @3,000 RPM
5) I spin them printhead out for 3 minutes @ 3,000 RPM
6) Then I vaccuum fill with an Eco. I have called TBA tech support and verified I am getting proper vacuum pressure.

I have put correctly cut tubes around my needles when inserting them into the cartridge, so the needle sits 1mm above the filter too, so I know it's not a peirced filter. I used this (SEE THIS) Service Information guide for that: (SEE THIS)

I have tried sitting the cartridges with the printheads up and the printheads down. Sitting it up seems to get more crud out, but I get the same amount of lines in my prints. Which way do you orient your printheads when spinning?

Most of the time, the cyan or magenta won't flow immediately and it takes considerable steaming, or pushing air through the top holes with a syringe, to force out air and ink. Do you think it's a good idea to do this? (I got the idea from (SEE THIS)'s airbox)

The reason I'm convinced it's air is because I can push the air out using the top holes and get almost perfect on one color, then when I take it out of the printer, push air into another color, then put it back in the printer, I get a bunch of lines in the first color that I had almost perfect! I think only air could act this way, and not crud.

When filling the 97's, sometimes the cyan and magenta will overspill during filling, but the cartridge only weighs 37g, and I can easily put the remaining 5 ml on ink them by hand (well using the manual buttons on the eco) does this have anything to do with air?

One more thing, is that I use the same cleaning method post above on my HP #75's and one day I accidentally filled the sponges incorrectly, I switched the cyan and magenta. The test print looked fine, except the color blocks were switched, so I know my cleaning method is pretty effective.

I also broke open a clean 97 today to see the remaining crud or air bubbles in the cartridge and everything looked very clean!
This particular cartridge had sat for a few days and the sponges were almost completely dry. I saw no air bubble due to it being so dry.

I know this has been lengthy, so to recap, here are my questions:
1) "If you have to do anything to the cartridge after filling it, it does not work." True/False?
2) What way do you orient your printheads in the centrifuge? Up or down? Why?
3) Is pushing air through the fill holes after refilling to remove air from the printhead a good idea? Why?
4) Do you see any steps in my cleaning that introduce air into the sponges?
5) What does the overfilling in vacuum when not actually full indicate?

I am kind of at my wit's end and would love to hear responses on all or even one of these questions, if you have a minute.