Hi All,
I confess my breath up is similar to Bill's - at the end of my breath up I do hyperventilate a bit, and pack if doing a deep dive or long dynamic.
For new freedivers I wouldn't reccomend too much hyperventilation. Thats why I said 3 or 4 quicker breaths at the end. Just doing slow deep breathing for 1-2 minutes reduces your CO2 a lot, hyperventilating on top of this will really reduce the urge to breath. Sure it's more comfortable but for someone that doesn't know their limits it can fool them into thinking they can hold their breath well beyond their limits.
Even without the hyperventilation, long deep breathing for extended time can really get your CO2 level low. My first six minute static I was slow deep breathing for about 5 minutes, until my hands got tingly(Symptom of Extremly low CO2 levels). During my static I felt very good, didn't get contractions until beyond the 5 minute mark. I stopped just after 6, because I thought I was pushing it too long, not because I felt like I had to breathe !
So for a newbie trying the same thing they would think, I don't need to breath, and continue holding until blackout....
By all means try out the different breathing techniques for dry statics etc, but learn your limits before using them in the water. For recreational free diving 1-2 minutes of deep breathing, and a couple of quicker breaths at the end should be plenty.
My 2 cents,
Cheers
Wal