When I was using a hand held mic, actually two of them, they were the Sennheiser E-855 and the Samson Q7, and never had a feedback problem with either one. I used the Bose L1 PAS and Bose L1 Compact(s) with both mics. The only time I experienced feedback with the Sennheiser E-855 was last week when I recorded a song on the S-950 and used the keyboard speakers for monitors, something I never did while performing live. The keyboard speakers were always turned off using a dead-plug in the earphone jack. When I used the Bose systems, they were always placed directly to the side of me at a distance of just 2 feet at most, thereby providing me with a great monitor of what the audience was hearing.

My EQ settings have been posted here dozens of times, so I'm guessing that the OP's EQ settings are similar, but I don't know for sure. If you have too much mid and high EQ, then feedback will be a problem with any mic other than my Crown CM-311A, which has a very short range and nearly impossible to develop feedback from any sound system. Unfortunately, some performers cannot use a headset mic, but that's because they need to use the proximity effect of a handheld mic in place of vocal control.

Good luck,

Gary