The DND Body Parts list issued October 1941 (my copy was reproduced by Alex Blair) includes a listing for the Winch and Derrick trucks including a side view drawing of the entire truck showing the support for the tilt which is different from the GS body, presumably to clear the derrick poles and cable when set up. The body differs from the GS in having extra external stowage lockers for the engineer equipment. As well, there is no listing of tailgate parts for the Winch/Derrick body.
The parts list gives a breakdown of the parts used to make up the body and their quantities in a chart that permits comparison of the GS and Winch/Derrick bodies. There is a separate drawing of the derrick poles, pulley and fixtures that lists a full dozen models of derrick that had different combinations of legs, pulleys and fixings. There is insufficient detail to figure out what the differences in capacity, reach and usage (if any) were for the different models.
"Miscellaneous Floor Parts" include "Strap - Derrick Pole Retaining" which gives an indication of where the derrick poles were intended to be stored when not in use.
About carrying 11 men per truck, was it normal for the engineers to use the run of the mill sapper (no offense intended) as the truck driver and mate? If so only nine would need to ride in back which leaves as much or more space per man as I was accustomed to in the duece and a half.
When Don posts the manual it may answer the question about differences in the models.
Also see the thread:
http://www.mapleleafup.net/forums/sh...&threadid=1692