A polish lasts as long as the roughness of the lane surface plus your rev rate allow. As far as I know, nothing can prolong that. More polish just changes the surface and you won't get the same ball reaction.
Secret Sauce is hyper abrasive. No other polish, in my experience, comes close.
(Brad, userid: bcwxxx, has used a polish for bearings called Monkey Jam axle polish, theoretically 60,000 grit (according to Brad) . I tried it but I can't get it to shine a ball like Secret Sauce does:
http://www.derbymonkeygarage.com/product-p/7999.htm"The particles that make up Monkey Jam are less than 0.05 microns." That's beyond micro-fine!)
The inventor of Secret Sauce recommended that you sand a reactive ball no finer than 1000 grit when applying Secret Sauce. If you took it to 4000 grit before applying SS, then I assume you're probably closer to 6000 - 7000 grit range as the finish in your LT-48.
You have to re-apply polish when the polish is worn or you see the ball hooking early. No way around that, that comes to mind right this second.