Is there a preferred string gauge for use when - and only when - an F-512 is tuned one half step to one whole step down? I am running into problems when I tune my F-512 down. The tonal quality vanishes, as does the intonation. My intuition tells me to move to a heavier gauge - the thought being that with a heavier gauge I can maintain tension at the lower tuning. As it is, the light strings I use now stretch and bend out of tune as I fret notes when the strings are under the lower-than-concert pitch tunings. Also, if I am correct and I should move to a heavier gauge string set, what is the preferred gauge for lower tunings?