If you're looking for something for lighter oil, I think the Ambush and Sidewinder will be too strong. With the same surface preps, those two plus the RS-P handle comparable amounts of oil.
Of course, the Ambush comes polished and the Sidewinder nearly so, so they'll be a small step down from the RS-P. I don't know that there will be a big of a gap as you're hoping, though.
If you're wanting Brunswick, I'd go with a Rampage. On medium shots and shots with broken down heads, I think it'll work better for you than particle balls like the Ambush and SW.
If not Brunswick, you might consider the Rotogrip Venus or maybe the Horizon. The Horizon shouldn't roll up quite as early as the RS-P since it's a pearl reactive with a highly-polished surface.
SH