Actually I could probably get 6 out of a tank, but I pit at 5 with it. Last time I ran the CV in a XXXNT was at a big track that had roughly 40 second laps, so taking an extra lap was a big gamble. That is with the tank set up ROAR legal (capped off fuel line inside tank to reduce volume to 75cc).

To be honest, I've never ran the CV with the stock head. I use the CVR head with it because I've heard the same as you (and had a spare laying around). I intend to start playing around with AE throttle restrictors to see if I can stretch it a little more.

Honestly I wouldn't worry too much about it if you're just getting started in racing gas. The CV or CVX is just what you need. Pretty much all gas trucks are overpowered, and for club racing 5-6 minutes a tank isn't really a big disadvantage.