I really like the 10" BG-14 burners also. The smaller 6" BG-12, which you said you already have one of, also works well at low pressure with a properly sized orifice. Not as powerful as the 10", but still plenty powerful enough to boil 10 gal. I can't think of any situation where you'd have all 3 burners going wide open at the same time, so a 200k btu regulator should be fine.
The jet burner you have will work too, assuming the tips are the right size, but it won't be as efficient as the banjo style, and you may have issues with flame control at lower levels. If you run a search you can find threads where people have capped off many of the tips on the 20 and 32 tip jet burners to make something a little more appropriately sized. Seems that the results have been mixed, but it might be worth looking into.