Hey
@Dave Merrill -- to help or explain, I have a few questions.
Are you switching to a single coil from a humbucker to play your cleans? If so, then you MUST turn on the filter boost "Kicker Coil." at 5db to make that single coil pickup hit the amp as hard as the humbucker does, if you want the volume to be the same when you switch pickups. This is originally a 1000+ Dream Rigs TonePack feature now included in the 1400+ Naked Amps.
Are you using Vintage style pickups (low output) or modern ones?
Are you playing the neck or the bridge?
Is neck louder than bridge (it should be on cleans due to bass content, but that is also pickup dependent).
Do you play live with cleans that are as loud as your leads?
Usually the Naked Amp cleans will be fine and in line with volume of low and medium gain, but the lead sounds a little louder. That's because oyu have to set lead levels in upper registers to hit -12db+, not chords down the neck like you would for other sounds. The higher up you play, the lower the signal strength (skinnier strings) - the lead presets try to take that into account and are a somewhat hotter.
I'll also add that Fletcher Munson effect can be tricky on judging loudness of sounds with different tonal content. I have had people swear a hi-gain amp is much louder than a clean and I showed them side-by-side meter readings being virtually equal using a looper for same chords, and they could not believe it. All that mids and chewy harmonic content and 4X12 cab can make you think something is louder than scooped Fender sound in a 1x12 open back, but 'taint always so, at least my experience has taught me.
The good news is, you have the tools to make these presets as loud or soft as you like -- that "last mile" to customize to you is always in your hands!
Last, (and this is important) the transients in many cleans are far more likely to spike the output, especially on higher output pickups. Many clean amp models have a very wide dynamic range.
For example, try the Shiva Clean with humbuckers then single coils. Whack it good and soft and watch it on a meter -- it is a WIDE range, transients spike stuff.
So - some of these cleans are dialed a little back to make sure the headroom is ample and enough before signal hitting 0 db, because if you hit that clean hard with your guitar/pickups, or add the provided control for Amp Boost to an existing preset then it could have clipped/digitally distorted, unlike the dirtier amp channels where that is less and issue.
If I turn the preset level back so it doesn't do that, then it's quieter -- but I do have to build in headroom so everyone avoids clipping when they fiddle with the switches or drive blocks (at least, where I can...).
Hope that helps put some context in it? You can always turn up the LEVEL control on a clean amp 1 db or 2db and see if that's better to your ears -- but remember you need to leave headroom to avoid transient spikes when you whack that guitar.