The question of normalizing volumes between presets comes up often.
First, go through the loud presets, look at what FX are programmed... and their settings. If you're new to this, it will help you learn what each effect does and how the various parameters affect the overall sound. There's a learning curve, but it's worth it. For example, loud presets will likely have high gain amp models with the drive and volumes turned up, and heavy distortion FX, etc. Softer presets will have "tamer" amps, lower drive settings, and milder FX with parameters turned down.
Everyone has their own approach to this. Here are some suggestions:
1. Group loud presets together; that way you'll avoid nerve-jangling surprises.
2. Do the same for soft presets.
3. If you find some presets are too loud, adjust amp settings or change amps, modify FX parameters or switch FX, etc.
4. If you find some presets are too soft, reverse the process used in #3.
5. Once you've got the presets within a roughly comparable volume range, you can then "fine-adjust" the on-board drive and volume level knobs for each preset and save the settings.
6. You can also use a second expression pedal dedicated to volume (I use an EX-1) for even more control, and for blasting solos... BUT that requires putting a Volume/Pan link in the effects chain.
Note: I find the "either/or" scenario of combining volume & wah in one pedal is limiting.
Finally, you can set up a "gig system" on your board: for example, saving rhythm or ambient tones in A & C with your lead/solo tones in B & D. (That strategy is used in the Firehawk FX.) By switching from A to B you can go from rhythm to solo instantly. Of course, you'll still need the volume pedal to bring things up or down depending on the mix.
VAX700's post in Leveling out volumes between patches... was marked as the answer