Actually you didn't fix the problem. Thunderheads are a good fixed head and out of a well tuned bow with matched tuned arrows they will fly perfect.....all you did by switching to a mechanical head is mask a out of tune problem and you will never get the efficiency out of your bow that you should. Spitfires in this case was a pacifier for your fast hunt but I hope you take the time to tune your bow prior to next season.

In one sentence you said the bow was shooting way left and you couldn't move your sight left enough, the next post you said all the Thunderheads shot way right.....

You bow is definatley out of tune regardless and measures should be taken to correct it regardless of broadhead choice. This will ensure your arrow flight is straight and impacting the target straight getting the most out of your arrows for penentration....