As far as I can tell, most players go with the same weight and drilling as the strike ball, just for the consitent feel. But there are players out there who use lighter spare balls for control and speed reasons, and I have heard of a few who use a conventional grip.
Personally, I tried lighter weight and different drill and I found it very distracting. But´that's just me and it is, nevertheless, worth a try, e. g. with a lighter house ball, before you get a serious spare ball drilled.
Anyway, I consider a spare ball to be an important equipment investment, esp. for corner pins, because it takes much of the oil out of the targeting and lane reaction equation.
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DizzyFugu - Reporting from Germany
"Put some make-up on your face - Make this world a better place!"
Kahimi Karie, 'Good morning world'