What is the purpose for the polish?Depth Charge has 1500grit polished box surface. So;
1 - If you are resurfacing it, use Storm Step Two.
2 - If you are polishing it to maintain the surface, use Moon Shine. It finishes to 1500grit. From my experience, Xtra Shine makes it a lot longer.
I use Columbia polishes too. 2000grit may be a touch more. Try 1200grit first, with spending more time on spinner. Due to the wearing out, trying smaller grit polish may be better.
It is discontinued now but Columbia's TECShine also works great on Depth Charge.
3 - If you need more length, than try Storm Step 3 in the first place. Or use Xtra Shine lightly.
Columbia 2000grit will be also great if you need more length. Take your time on the spinner.
If Columbia 2000grit or Storm Step 3 does not work, go with Xtra Shine, Diamond Gloss or anything that says "high gloss" on it..
Hope this helps,
Burak
PS: That's hell of a ball by the way