Yes, I have tested literally hundreds of different ads on Google. Science slogans work best (highest CTR) although with crypto going mainstream so quickly, crypto buzzwords are also getting some traction now.
Regarding the bounce rate, that's the website metric really, not an ad metric. If this Initiative is approved, I am going to point some of our ads to gridcoin.science and measure any difference in bounce rates.
Good idea for Bing ads, I will look into it! We should spend some $$$ there too.