I drilled out my broken fuel screws. 1979 GS850

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On my 79 GS850 all four of my VM carbs had broken fuel screw tips, stuck in of course. Instead of looking up helpful tips on here I used some MAC Tools angled pics for days without success. I then decided they are now broken carbs and decided to try to fix them. With a very fine drill bit i drilled slowly at a perfect 90 degree angle without the slides intact. I cleaned very well to make sure of no metal shavings before putting everything back together including new fuel screws. I tuned it at one turn out fuel screw(bottom)and 2 turns out on the air screw(on the side of carb). It ran rich, so I figured the hole was bigger now and turned the fuel screw one half turn in and it still ran rich. After many quick rides, backfires, hiccups and fouled plugs i have it running great at seated fuel screw and one turn out air screw. Has anyone else been in this situation and if so what worked for you? Also could this be wrecking the bike in any way?
Thanks in advance for your help.