Invalid Link Removed
Not advocating purchasing anything from GC, but I use one of these clipped to the bass side bridge adjuster, with the capsule aimed directly at the top over the bass bar.
I learned this from an amazing live sound engineer who argued that since the bass bar is the loudest vibrating source on the top, it's the best place to get a pure signal. It's often a little thick at 100k, but the sound out front is pretty authentic. A skeptical engineer came up on stage recently and shook my hand, professing his initial doubt but that "it sounded like a big loud bass."
BTW, using a mic with an amp on stage is often a recipe for feedback. Most of the guys using mics are doing so exclusively for FOH, while monitoring through a pickup- amp on stage. The only ones where mic only works for me are small intimate listening rooms where the mic-amp combo is giving a little nudge.
Also, the AT mic requires phantom, which is a button away on my acoustic image amp.