The BWP, with a moderate-strength drilling, and a Cherry Vibe, with a stronger drilling, would give you a nice arsenal useful on THS -- especially if your current fave on that shot is the RXS300. The reason I say this is that the RXS300 is a ball that performs well on most drier mediums and shorter patterns. Therefore, I feel safe in saying you don't need something that is going to hook like crazy -- like a No Mercy, etc. The pearl reactive covers on both the BWP and the Cherry should cover most conditions that you might encounter, and give you a decent look on the lanes.
The BWP is going to be about as long as your RXS300 (maybe a few inches shorter), but with a more angular and bigger backend. The Cherry should go longer and have a less angular reaction.
Hope this helps. If you are not bowling in a ton of tournaments, and you are, rather, just bowling in a league or two every week, on a condition that is pretty close to being the same each week, I don't see any reason that you could go wrong in selecting these two balls.