Simply put, you can make the Sinister - or any ball - more versatile by some combination of smoothing out the cover (abralon) and adding polish. To be honest, I sometimes find "heavy oil balls" to be at their best when you do this because then you can use them on medium to medium-heavy as opposed to only for true sauce. The problem with the Sinister is that the OOB surface is already at 4000, which is usually as smooth as you're going to get. Now, you can obviously add polish on top of that. The problem is that it may be a pretty big pain to keep wasting time and money on polish for the nights when they've gone a few days since last they were oiled only to have to scuff the polish right back off on the nights when they've put it out there fresh and heavy. Because of this, I would bite the bullet and consider spmcgivern's suggestion of considering another ball to go between the two. That way you can keep your Sinister ready for the soup, which is what it's designed for anyhow, and you can have another ball ready and waiting for when they are less oily. Thankfully, there are a lot of good options in the mid-priced range these days, so you can probably get something you need without having to spend a fortune.
