Of the 3 you mentioned, I would choose the Equal-i-zer based on what I know about these. The reese StraightLine (Dual-Cam) gets the best reviews here on the forum. If you want the absolute best set up, look at either the ProPride 3P or the Hensley Arrow.
To JBarca's point, a trip to the scales is probably a good idea when you get it all set up and packed. Bear in mind a toy hauler is unique in that the loaded tongue weight is LIGHTER than the dry tongue weight, primarily because toys get loaded behind the rear axle. Some toy haulers are so tongue-heavy when dry that they're almost not towable without something in the garage.
What happens to the loaded tongue weight also depends on where the fresh water tank is, whether you fill it, and most toy haulers have gasoline tanks built in as weel, so more variable weight. You don't want the tongue too heavy for that 150, but you don't want it too light either or it'll sway all over the road.