splendorlex: First, you have to decide what you want to accomplish in bowling.
If you're going to be bowling league in one or two houses (and nothing more), then hooking at left side spares will be easier to master and probably get the job done.
If, however, you want to venture into the world of tournaments in strange houses with unpredictable conditions, you're going to have to learn to throw straight at all single pin combinations. At first this is painful and error prone, but to be successful it's a necessary skill to master. For left side combinations, it really doesn't matter if you go straight up the left channel or go at a slight angle from the right. The main thing is establishing a technique that is comfortable and consistent.
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"Yeah...what Jabroini said"