Smart man here. Look into Audix (OM5, OM7) mics. They are great, affordable and are designed to eliminate/deter feedback. Shure SM58's may be industry standards but there are better mics out there.Don't know if it is too late or not but anyway, the Audix OM5 is a LOT better in the gain before feedback department (about 9db difference!!!) than the 58 or Beta 58 (its shure equivalent) and sounds REALLY good (better than either in my opinion). You can pick them up everyday at GC for $99.00 The Audix I5 is a better mic than the 57 or Beta 57 (and a TON of others) and can be gotten at GC for $79.00. These mics along with an Audix OM 7 and a few Audix drum mics have replaced most of my old "standbys" that I have been using for the past 25 years or so!! Very good products PERIOD!! ESPECIALLY for the money.....
Peace,
T