Obtain drilling/layout-patterns from the bowling-ball's-manufacturer;
Measure the bowler's thumbs' diameter/length, & fingers' diameters/lengths,
also measure the bowler's fingers & thumb grip-angle/pitch.
The drilling-layout is marked on the bowling-ball's-surface.
On a regular/vertical or adjustable-articulated/special drill-press:
the bowling-ball is clamped-down & drilled 1-hole at a time,
the bowling-ball is re-positioned/re-clamped according to the drilling-layout for the next hole,