I actually hit my own personal sweet spot on my first fill.....but didn't realize it until I went and got another fill. Long story, but I ended up too tight and had to have all the 2nd fill taken out. It actually made my first fill volume on the too tight side too. So now I am at my first fill volume, but have more restriction and am slightly still too tight. Don't know why at the same volume it feels tight, but it is.