If you have one single U-joint on the end of the column, one single U-joint on the steering box shaft, and one piece of shaft between the two, you do not need a support bearing. A support bearing is needed for each additional piece of shaft and the corresponding u-joint used beyond the first piece of shaft. Another way of saying this is that the total number of support bearings needed is the total number of single U-Joints minus two, or the total number of intermediate shafts minus 1. Theoretically, you could have an unlimited number of intermediate shafts between the steering box and the column if you follow the formula.
Support bearings are also recommended for double U-joints and when using a vibration dampener.
Flaming River offers the following which eplains the need for a support bearing in a three u-joint system.
Flaming River recommends shaft angles of 15 degrees but says 30 degrees is acceptable. Borgeson Series 16 U-joints will accomodate angles up to 35 degrees.