The right angle finder - specially one with magnification option, is quit useful for low level or closeups. However, the eye relief is such that when you move your eye further away you see much less of the whole field of view.
A waist level finder presents a laterally inverted view while the top view from the Ricoh TLS401 is fully corrected just like the eye level view. However, it also has a very short eye relief like the right angle finder.
OTOH, sport finders - like one for the LX+FB-1+FC-1 below, are designed with eye relief as a main consideration. Although you can move your eye further away from it compared to the two options above, it will also begin to crop the field of view with distance.
The waist level finder is really the best option for the OP pending further clarification about what the XK waist level fails to deliver. The built-in magnifier also adds to the versatility.