This information from RCA service literature should answer your questions:

The tube should be installed with the high voltage connection approximately at the top. The final orientation of the tube will be determined by the position of the ion trap "flags".

Look at the tube gun structure. The second cylinder from the base, inside the glass, is provided with two small L shaped metal flags. The tube must be installed so that when viewed from above the neck, these flags stick out horizontally, parallel to the chassis.

Slide the ion trap magnet assembly over the neck of the tube with the large magnet toward the base of the tube, and with the arrow on the assembly on top of the neck pointed toward the screen. The front magnet is moveable on the assembly, and should be positioned so that the gap is on the left side when viewed from the rear, and even with the gap in the rear magnet. The assembly should now be positioned so that the rear magnet is directly over the "flags" on the gun. (Turn the set on, and set the brightness control fully clockwise and the contrast (picture) control counter-clockwise).

Starting from this position, adjust the assembly by moving it forward or backward, at the same time rotating it SLIGHTLY on the neck for the brightest raster. Reduce the brightness control setting until the raster is slightly above average brightness. Adjust the focus control until the line structure of of the raster is clearly visible. Readjust the ion trap assembly for maximum raster brightness. The final adjustment should be made with the brightness control set at the highest position where good line focus can be maintained.