You need to know what each of your bottle weigh empty. I stamped the bottom of my bottles so I would know the weight of each one as they can vary 3-4 ounces from each other. If you put more in the bottle than it is rated at, like 2 lb bottle or 2.5lb bottle, or 5 lb etc. it can blow the burst disk. this are usually rated fairl high i think like 1800lbs and if you get that kind of pressure against the solenoids they will not function properly if they open up at all. You need to weigh the bottles and you also need to have a gauge on the bottles on hot days when they are sitting around so you can monitor pressure. Do you have a purge and a gauge mounted on the bike so you can leave the line each time with the same pressure? i alway like to leave the line with at least 950 lbs of pressure and I also would make sure each bottle weighed the same as the last pass for consistency. you can get a mail scale at a office supply store for about $40.00-$50.00 so that you can monitor the weight.
As far as leaking by the fitting you either did not have the fitting tight enough or the line tight enough.