I think I am starting to see what you mean. I am still mildly confused, because the teleport indicator existed beforehand and kinda sorta already checked if the teleport target location had enough space to place you, it just didn't try to place you on the ground.
You can alleviate some of the issues that happen in small spaces, by reducing the spectator width and spectator height. I would be a bit careful with the height though, since that is the offset to the ground in seated mode, having a spectator height that does not roughly match the actual person, can give you a false sense of scale. The indicator figure is exactly as large as the configured spectator, so if it is "very large" something seems off.
My advice to users of VR is to first slightly press the trigger button to get the teleport indicator, then to aim at a spot on the floor where they want to teleport. This best gives them the feeling of what will happen. Just squeezing the trigger will generally result in lots of confusion and disorientation.
Alternatively, I have heard good reports with people using views to move people around in the model. Before the presentation, a number of key views are configured and during the course of the presentation, the spectator is guided through the views and effectively never modes on their own. This is, so I am told, the most novice friendly solution.
Can you post or send me the types of geometry where you are having trouble moving around in VR? I will have a look and see if there are ways in making it less error prone.