I agree that installing an under the saddle PU is a very tricky business. You can do some serious damage and loose the original tone of the guitar too!
I also find that a under the saddle PU system most times will be uneven output from each string.
Go into any music shop and using an acoustic amp and a set of headphones audition ANY acoustic electric,, slowly one by one listen to the volume of each string.
The best I've used for even sound was the LR Baggs with the solid brass bottom that Seagulls used to use. They now use the common ribbon type and they suck now too.
So I have become a fan of using a mike again.
I use the Saddle PU for rhythm and the mike for leads and fills when playing live.
And don't toss out the old Dean Markley, Those were good PU's.
My son just bought a sound hole PU system and it sounds great,,, I think it's called Gold Tone??