All of this makes perfect sense Dave
It certainly is advantageous to have access to the Table of Scale Drawings for each type of bolted arrangement. Being in scale....just understand the stud size, then copy the relationship scale x the nut = AF size and height.....top face profile......washer thickness & diameter etc etc
[just to confuse
the top Table depicts nuts as the hex point to point, the second table depicts the nuts in across the flats]
The fitment of the Parallel Motion Shaft mounting Plate is absolutely typical of the ingenuity of these Designers ......the base of the block is flat, the frame has a 'cast in'' then machined set of relief pads.....5 rectangular width wise finger pads [this makes the machining of each support plate surface much easier and in ensuring flatness - it would not be uncommon to understand that each of those 5 finger pads were hand scraped & blued to ensure accuracy [flatness, squareness, triangulation between each other pivot axis in the linkage or arm]
The frames also has width wise support up-sweeps cast in at each end of the support plate area. The plate has 1 1/8" elongated holes, and whilst not shown in the Drawing....final during final assembly and positioning of the PMS mounting.....steel '
Keeps' [full height x width sized packing pieces] would have fitted between the ends of the PMS mounting plate and the corresponding cast support up-sweep
We can see, & naturally the identical arrangement would be applicable to the top/main engine shaft bearing block to frame interface
The engineering philosophy in this engineering was carried over and used in military [Naval] armaments in a parallel time frame with the building of these machines................... Derek