Something I found last night that works for me. When using it for clean tones, or specifically for the cabs I have saved for recording clean tones, I like to have the poweramp simulation on even when using the power section from my heads. Using a bassman cab with 6l6 power, or /13 cabs with el84 powersections sounds more natural and sparkly to me, also outputs louder with out clipping the front end like clean channels tend to do vs. overdrive.
My two cents