Paintball co2 UFA with gauge accurate?

[cbehr]

Is it worth getting a universal fill adapter with a gauge on it to see how full the tank is? Are they accurate or doesn't it even matter as a tank will show full one second and empty another with very little middle ground?

I'm trying to keep my rig as small as possible so I don't want a normal fill gauge on the regulator.

See below:
http://www.ebay.com/itm/281070965801?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

 

[RiverCityBrewer]

The only way I know to accurately measure co2 in the tank is to weigh it... pressure of co2 means nothing as it is all temperature dependent, and you are correct, once all the liquid co2 has turned to gas, the pressure in the tank will drop rapidly.

 

[cbehr]

So this would work in a similiar fashion to a standard c02 regulator on a 5lb tank?