Sequencer Volume

I have synth with an internal 16 track sequencer that we use on stage to add synth parts to some of our tunes.  The biggest problem we are having is a consistent volume sequence to sequence.  We sat down a couple of times and played each tune through the PA and mixed and adjusted volume levels, but they still are inconsistent enough that I have to spent quite a bit of time on stage adjusting volume.   Any suggestions on how to get a consistent volume?

Yes, the sequencer is simply playing the patches on the synth.  And, Yes, I have noticed that some of the patches have significant volume differences.  I've spent alot of time mixing each individual sequence to get a good (I think) balance per tune, but again getting a consistent level for all sequences has been the challenge. 

So until we can afford a soundman you're thinking that I'm stuck riding the volume fader?

That seems like more work than it should be :)  I can adjust the volume of each of the 3-16 tracks per sequence and get a nice mix within the sequence.  But I have 20 different song files that I'd like to have mixed to a similar volume...that's the challenge.   Does that make sense or am I missing what you're saying?