I recently acquired a used Leica TCRA1102+ that's having communication problems. It's in the shop for diagnosis, and if it can be repaired at a reasonable cost I plan to put it into service. It came with a GRZ4 360° prism, which is surprisingly large and heavy. I'd like to reduce the weight on the rod, and I see that Leica also sells a GRZ101 360° prism that's much smaller (tiny, even). According to the GRZ101 data sheet, it can maintain lock out to 250 m in heavy heat shimmer, and out to 350 m under favorable conditions. I'd be interested in hearing from Leica users about your experiences with the two prisms. The GRZ101 isn't cheap ($650 or so from what I see online), but if I can knock a pound or so off the top of the rod and still work effectively, it might be worth it. Thanks!