I would consider myself an average bowler. Alley I bowl on has older wood lanes & Med. oil. Had been using and older Rhyno ball( that actually had the pin on the left side of fingers, pro shop said was backwards for a right handed bowler)... anyway was going to have this one plugged for me. While waiting for this to be done, bowled 2 nights with a Morich Seek and Destroy. Had a pair of 600 series, and I am only a 150 bowler most of the time. Loved the smooth arch to the pocket this had, very comfortable ball. The pro shop offered to sell me a used Track Freak Out for just the price of drilling. Well don't care for this one as well. It has a major back end cut to the pins, that I could get used to I guess. But would really like to find something that had a smoother back end like the Morich.   Any ball suggestions or surface prep I could do to the Track ball I now have? Had been Eye balling Columbia Freeze this a possibility?

The Freeze is very strong off the pattern.

My feeling is surface preparation is a major factor in how a ball is going to hook (sharp vs smooth).  If you still have the seek and destroy leave it as is.  If you want the track to be smoother and more predictable, I would dull it up to 600 to 1500 grit.  

Personally, I would leave the track snappy.  It would give you a nice 1-2 punch in case the seek and destroy isn't working on whatever lane conditions you are working for.

To answer your other question as to which balls are more gradual - They all could be.  With most companies, their covers and cores can be adapted with drillings and surface prep.  The thing you need to ask yourself is if you want a heavy, medium, or dry lanes ball and adapt it off of that.