I have the TC Harmony pedal too for my vocal.I also use a Radial PZ Pre DI for my acoustic with XLR going to mixer. My guitar is a Tommy Emmanuel Maton BLuegrass style with Piezo and Mic pickup blend.Ive tried both PAD on and PAD off with acoustic there seems to be no difference to sound apart from obviously having to bump the Level on mixer up with PAD on.I still havent got my head around undersatnding the db thing…(Im a bit slow )lol.
May I ask what DI Box do you use for your Acoustic?and I may have missed it in your explaination but do you use the PAD for your acoustic channel?