I've realized that there is a difference in level between some presets? How to adjust the overall level of a peset?
There isn't a control for the overall level of each preset, but you can individually change the effects level which is usually the cause of differences between presets. Often, presets with lots of effects are louder and ones with i.e. Transducer are quieter, since we author them a bit lower to avoid feedback.
Since the method above will take some time adjust things to even out for each preset I would suggest to run the main outs of the box through a compressor to limit/normalize the output as a whole. It'll depend on your available gear and your comfort with stuff like that.