Not sure what models the Line6 has but the Fender Twin should be there and that was the standard amp for many years (I still use one). The big Peaveys will probably not be there, but a Roland JC120 might be close.
Have a search for (the late) Bobbe Seymour or (the very much alive) Micky Adams on youtube. That'll get you onto some good stuff and you'll be presented with loads more on the sidebar.
Next, not sure what you mean by "detuning the corresponding strings"? You know that they re-tune strings, so that can't be what you mean.
As a tip - when you describe knee-levers it's best to say what they do, rather than just where they are. When you say "Emmons" we know where your pedals are, but the (usually 4) KLs have no standard placement; so your left and right one could perform any number of functions.
They are generally named depending to the position and then function, like this= LKL (left knee to the left) - "E's to F"; LKR (left knee right) - E's to Eb (which is what mine do). Also using the string number(s) is OK too, rather than naming the the note like: RKL - "half tone lower, 2 and 9" and RKR - "half tone raise, 1 and 7".
If you check out players' copedents you may also come across a "V" for vertical (I've got a "RKV") or even "in" and "out" ("RKL in", "RKL out") meaning that their guitar has two KLs in the same position, one positioned nearer and the other further away from the player (that's how you get ten or so knee levers fitted in) so they have to hitch forward to get at the outer one.
Hope this is helpful - and do get back to us about the "detuning? We want to help.
By the way, Bob has a very sound and well earned reputation as a techy in the PSG world. ZBs hold no terrors for that man!