That last part is why I am reluctant to believe that poll result. Trump's voter base is largely motivated by the fact that he is a political outsider. Then there is the cult of personality side of things. Neither of those should be affected by the conviction.
Also, and I admit to being in a bit of a bubble myself, I only know IRL or read about people who are going to "vote harder" for Trump, vs not voting for him, because of the conviction. It's actually hard for me to believe the "one in ten", since the average Trump voter that I'm aware of would not bail, but rather rally, because of the conviction. As the ridiculous amount of $$$ that came in within 24 hours seems to indicate. Apparently his May total for contributions, with ~$140 million of them being from the <$100 donation cadre, reached almost $300 million.
FTR, I have never been contacted for a political poll in my entire life.