I’m still stuck on the Instant brainworms.  Just what I needed: another rabbit hole.  Blame goes to that “Fan of the Rad Sh*t”.

So, you want me to give up my ‘trade secrets’?  Joking, they’re hardly secrets. When I’m running through a mixer for isolated parallel, I go your route.  Effectively, you can do the same thing in-the-H90-box.  I try to make my uploads as universally useful as I can.  And I’m guessing most Insert Progs are used inline with the amp(s), like my live / programmer setup.

Here’s my basic philosophy.  Start out from scratch with both Presets at 100% wet*** (when there’s a Mix parameter) in Series or in Parallel.  Then 50% Program Mix in Parallel with all of that.  It’s my master balance between dry & wet, and it works well with the modulation effects that often do the same (ex. – phasers).  Great place to begin.

Often it ends up staying right there, because it has the results I want to hear.  I figure if it’s too much wet or dry for anyone else’s taste, it’s easy enough to tweak down or up.  That’s the reason I call out that particular parameter setting in every description that accompanies my uploads.  (There is never enough room for me in the Program Notes).

The exception(s) prove the rule(s).

• I like to tie Program Mix to an expression pedal, for the ability to add extra emphasis or a crescendo to the wet signal.  Often not a lot … sweeping 40-45%.  I have also had to go in the opposite direction (50-35%).  The combination of parameter mappings in the expression pedal become overwhelmingly wet or loud (I’m looking at you, PolySynth).
• There are also times when 50% is way too much for my own tastes.  On the rare occasion I’ll upload something more subtle, Program Mix will get dialed down.  The philosophy at my 1st recording studio internship was dial down (reverb, in this case) until you can no longer hear the effect, then take it back up a notch.  Philosophy #2 – Reverb is the opium of the bad musician.  I never forgot that, even as I break those rules.
• Another case – mainly in a Series routing, but sometimes in Parallel – is that I want to hear just enough of the instrument alongside the effect to enhance the attack portion.  So, Preset A / B Mix might get dialed down from 100% to 75-80%.  The same goes (in Series) when I want Preset A (at 100%) to ‘bleed in’ some of its processing intact.  Then dial back Preset B Mix to 25-50-75%, now having a blend of A effect with A+B effect.
• OK, one more:  Both Presets in Parallel, map the Mix parameters in opposite directions to the (P) HotKnob.  I have an entire Program List that uses this tactic to blend the amounts of two similar but distinct algorithms.  Then adjust the Program Mix.

So that’s my TL;DR story on the Program Mix control, and I’m sticking to it.  You asked for it, Tony.

***I’m speculating that you exclusively use the Preset Mix controls for your balancing acts?  That’s what came to mind when you said that you heard no appreciable difference with Program Mix.

I look at that this way: You’d have Preset A dry & wet in some proportion, and Preset B dry/wet in some proportion.  Then when you dial back Program Mix from 100%, you’re folding in more dry, diluting the amount of effect(s) coming through.

Maybe I’m missing something in your setup / routings.  I’ll do a deeper analysis on your uploads to see where we may differ on approach & philosophies.