You are right in your assumption that bench focusing is centering the lamp in the
reflector. On the 360Q there are 3 screws on the back of the lamp cap that can be used to adjust the center. They are in a triangle pattern, and should be slotted head screws. There should also be a center screw that adjusts the depth of the lamp in the reflector. You have to use all 4 screws in concert. To bench focus, you should set your fixture up pointing at a flat neutral colored wall or drop and get the focus as sharp as you can. Then adjust the screws to create a flat even field of light.
As for lamps for the 360Q, there are many choices depending on what you need. You probably want to look into the GLA or GLC for your 575w choices or GLE and GLD for 750w choices. We have a bunch of threads on replacement lamps for the FEL, which is probably the 1kW lamp you have been using. Try a search.