I use my Mastermind on the fresh with some volume with great results.  Keep in mind that no ball hooks in oil.  Some will start to read the lane a little, but every ball needs to find some friction before it changes direction.

I usually play a swing shot from the oil to the outside and let the ball return to the pins.  The Mastermind has been everything I could ask for in that regard.

Any one of the three would be a good choice for heavy oil conditions. I have a Mastermind that is drilled pin up, and a Ruckus Feud that is drilled pin down. I have kept them box surface and both balls get down lane and don't hook at my feet. I haven't seen the Yeti Untamed except for a video on youtube, but I would think that it is a strongest Radical ball. I use my Mastermind on a house shot, and anything with more volume to get through it but still have enough energy to hook down lane. I have used the Ruckus Feud when I need a more hook than the Mastermind because of the pin down drilling. I have used the Ruckus Feud on heavier oil conditions to help control the backend motion.

Why not the original Reax from Radical? You can find them for around $100 now, and I can attest that the ball handles oil without problems. Also, its got the patented "offset" technology hitting power.

In short, I love my Reax; however, if your options are limited to these three balls, I would say go with the Unleashed (simply because of your "distaste" of asym balls).... its a very strong symmetrical ball; you could even lay it out with a MOtion hole in mind..... which would give you even more hook overall when compared to other drilling options.

Personally, I haven't had much "success" with Big B's high end asym balls; had the Mystic Aura (while not an "oiler") and we didn't "agree". Also had the Endless nightmare and that too, didn't impress me (actually took surface up in grit and added polish to use it more often, it did require a boat load of oil up front and clean backends to roll well).

Motion Hole link--http://forum.bowlingchat.net/viewtopic.php?f=13&t=7374

The Yeti Unleashed can handle oil and like BowlingBallSale suggested you can use the MOtion hole layout and if that doesn't hook enough you can take the surface from the OOB 2000 down to 1500 (Abralon/Saair) and gain about another 5 boards of hook.
I have mine drilled with my favorite layout 45 x 5 9/16 x 70 (my PAP is 5.5"-> 1/8" ^). Here is a link to a picture of it on the Radical Site http://scontent-a.xx.fbcdn.net/hphotos-prn2/t1.0-9/s720x720/1904274_292569954230864_111481273_n.jpg

I have a ruckus fued and a mastermind. To me ruckus fued out hooks anything I have ever had by A LOT. Mastermind for me is longer but it is drilled different than the fued. If you checkout lane side reviews on facebook they have a video comparing Ruckus Fued, Endless Nightmare and Mastermind.

I have the mastermind and the unleashed.  The shape of both are very similar.....with the same surface they are very close with the unleashed being slightly more angular but a couple boards weaker overall.