Anecdotally, I've found yohimbine seems to help substantially when combined with fasted cardio once I start to get close to that 10% range. Could be just because of the fasted cardio I suppose, but either way I definitely notice a pretty big difference. My problem is I have a really hard time fitting in morning fasted cardio with my current schedule. And a 4 hour mid-day fast is rather difficult as well considering I practice intermittent fasting to control calorie intake. Thats why I'm curious if yohimbine would still be effective using the way I described in the OP. I suppose if it's not, I can suck it up and start getting up at 5am to do my fasted cardio like a good little bodybuilder.
Oh and the boner thing. Yeah, that's definitely real.