As I wrote earlier, I decided to go with the CB-58FTR instead of the CB-48FTR. In for a penny, in for a pound!
It arrived last night and while I haven't had a chance to do any real world testing, I do want to share what I worked out about how to use the tilt lock mechanism as the manual the head came with wasn't at all helpful, how to use the base rotation index, and my initial impressions.
Tilt lock:
1) Lock the panning base and fully loosen the main control and the tilt lock control.
2) Set the roll (left/right tilt) angle and set the tilt lock.
3) Set the pitch (fore/aft) angle and then lock the main control.
Overall initial impressions:
It's very well built and not as large as I expected it to be. The controls feel very positive.
When engaged, the click stops for the panning base feel positive but not stiff. There is a spring loaded button in the center of this control. With the head oriented so the index mark on the side of the head is at 0 holding down the button keeps the head from rotating when installing or removing the head from a tripod.
The "stop ring" on the main control is pretty easy to figure out. Basically it's a tension control so you can set a minimum tension that is appropriate for the weight and balance of the camera and lens (or if you shoot pans or macros, the camera+lens+rail(s)+ vertical arm) of your panoramic set up). It's easier to use than the thumbscrew tension control on my Arca-Swiss B1 and B2 Monorail heads.
The way I have decided to set up the CB-58FTR is with the main control to the left and the panning and tilt/lock controls to the right side. The main control is at about a 170-degree angle from the tilt-lock and panning control. This places the drop down slot facing forward.
I have also replaced the basic (tiny) platform the head came with a Really Right Stuff PC-LR panning clamp. As a general note I find that having panning mechanisms at the base of the head and at the camera level is a far better way to work than just having a single panning movement.