About this detail of the Tiger
On the hull beside the idler wheel there is a track-pin return plate. The instruction leaflet suggests that you should put it horizontal if using the large idler, or tilt the end downwards with the small idler. In this way it will always bump the track pins.
But in fact, the Germans did not have this good idea until May 1944 [1] . So for a vehicle built before this date, you should position part B20 as if you had a large idler wheel.
[1] DW to Tiger 1