[Pegleg]

I also have a "low" or I'd characterize it as "weak" voice, some days worse than others..... I've never owned a Bose but had the same issue with feedback; tried a lot of remedies, including several different mics and even a feedback destroyer. Aside from the specific advice relative to the Bose, which I have no experience, I'd say you've already gotten some good tips.... of which the best, in my experience are placement (mic to speaker), understand gain staging and, learn to use close mic technique. The issue you're likely to run into relative to close mic technique is proximity effect, some mics are more sensitive than others. The one I've found to be most "forgiving" is the Audix OM7. Oh, by the way, the feedback destroyer works, problem is, whilst it's "killing" the feedback frequency, it's "killing" the vocal quality of your voice. Whatever "sparkle" you have in your voice will become duller with each deployed filter shot. Hope this helps, good luck!