my game sounds alot like your's except I'm a righty.I really like the Blast Zone polished for flat mediums and some carry down,might want to try that or an ultra.the twisted is smooth but has good snap/roll off the dry but carry down gives mine alot of trouble.the best skid/snap ball I've ever owned is the Intense Inferno!if you can find one it's worth it.
I really like the cover/core combo on the Blast Zone and I highly recommend it.oob it's a great heavy oil ball and polished it's a strong med oil ball.I feel it covers alot of conditions as the other two I've mentioned are more condition specific.
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The harder I try the harder they fall