You have to remember that Storm's Step 2 is not really a polish; it is a compound. Its purpose is to take rough balls (like a 360 or a 500 grit surface) to a higher numerical or finer grit level. When you apply it to finer grit levels, like 1000 or 1500 grit, as you did, it will allow the ball to have a polished appearance. The problem with an aggressive compound like Step 2 is you really change the entire grit level of the ball to an unknown degree. This is why it's best used for 2 purposes:
1) when you consistent enough to know the finish you applied and can repeat it consistently and,
2) when you playing with finishes on your own balls, just because every time you stop applying it, it is really an unknown quantity for your personal use. This is good when you can repeat the process, every time.

As for polish, it is best and much more consistent, if you apply a known base sanding grit, like, 1000, 2000 or even 4000 grit, and then apply a good polish, like Xtra Shine over it, to create the low, medium or high gloss finish that you or your friend need/want.

Since you have created and unknown degree of base and polish, it is very hard for anyone to even make an educated guess as to how to make the ball hook less.

I would suggest starting with a 2000 grit pad and give the ball a through sanding, then apply a dose of a good polish, like Xtra Shine and then see how he likes it. If it still hooks too much, sand it to 4000 grit and then give  a strong dose of Xtra shine.

FYI Xtra Shine is, in a sense, an extender of Reacta Shine, as it has finer abrasives in it. Extenders usually make a ball go longer but snap harder in the backend and more sensitive to the amount of dry and to carrydown.

Also remember that the shine or finish from all compounds and polishes is determined by the human factors: how much is applied, how long it is spun by the spinner, and how much pressure you apply with what kind of rag/towel.

The class of polishes that truly reduce hook and backend is called Slip Agents. There are very few of them around: Powerhouse's Delayed Reaction, Neo-Tac's Control-It and Valentino's UFO. Once applied, they needed to be sanded off, because they clog the balls' "pores"/openings that absorb oil. They reduce hook and backend by reducing the amount of oil absorbed by resin balls.