2 days at 30 lbs constant will probably overcarb it. I get it cold, put 30 lbs on it and take the line off. I top it up in the morning with 30 lbs and then let it settle in at 4-6 lbs, depending on style and temp.
Purge the keg and set your regulator at your desired pressure and serve. If it's not overcarbed, it should be perfect. If it's overcarbed, just take the gas line off, purge it completely and let it sit for a few hours. Purge it again, replace the gas line and set to enough pressure to serve. If it's still overcarbed, repeat.
And don't forget that foaming can happen because of short beer lines even if it's carbed perfectly. Just keep turning the serving pressure down until it comes out well.