If I could go back to the 7 string debate for a sec...
I wield an American Standard Fender Stratocaster w/ the standard tremelo - you cannot detune the standard trem w/out taking the other 5 strings! I wish I knew about this when I bought it 'cause now when my strings get close to changing time, I never gig without my Peavey T-60 as back up for fear of when a string breaks, it all goes out of tune!
Anywho...
The ZOOM GFX 707 has enabled me to dial in a custom 'detune' setting where I can change the whole set down to DAFCGD for added depth.
I know all your major multi pedals can do the same thing - try it.