If you're on really truly heavy oil, forget about the "snap at the end."  You won't get it, with anything, ever.  If the oil is truly that heavy all you can hope for and what you should strive for is something that will tilt up on the back and hit with decent angle.  You may well have to play straighter than you might like, but the name of the game (to quote Hose) is scoring, not style.  Do chicks dig the big hook?  Maybe, maybe not, but that's not the point.  What they really dig is high scoring by any means possible (to quote Malcolm X).  What you want is heavy roll, angle of attack and slower speed.
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"To plunder, to slaughter, to steal, these things they misname empire; and where they make a wilderness, they call it peace."  (Tacitus)
"If one tells the truth, one is sure sooner or later to be found out. " (Wilde)

If you sand your ball,most likely it'll hook sooner.If you don't have that much hand the ball will move in the midlanes but,will lose power in the backend.I suggest cleaning the ball really well.I would also suggest moving right into you hit the pocket.I love to see the ball hook but,if you have to move right and play straighter do it.I see so many people fight the oil and lose.I see people try to throw their normal line but throw the ball slower.Take your game outside.On tougher conditions it's not the bowler that throws the most strikes.It is the bowler who can hit the pocket and leave single pin spares.If you are bowling with a good team however,in practice throw sanded balls over your teams area.This will break down the lanes a little better for you.Then switch to your normal balls at gametime.It all comes down to the basic statement:If you miss left,move left.If you miss right move right!!I hope this helps you alittle.
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FIRE ON THE LANES,ICE IN THE VEINS!!!!