SPECIALLY DESIGNED RULER!
Please don't pretend this is a big deal. In any formal or semi-formal setting it is not uncommon to use them in order to make sure everyone has equal space at tha table and there is enough room. Plus it makes things look arranged and nice. Bethel did not design the "specially designed ruler" to arrange placesettings, believe me.
In my brief career waiting on Bethel tables, I never even saw anyone use it, although there was one in the storage room. There are just a handful of measurements you remember, for instance: the plates are set a finger's width over the edge of the table, with the fork tucked under on the left and the knife and spoon on the right. The smaller plate is set at about 10 or 11 o'clock right next to the large plate. The glass is set on the right at about 2 o'clock. The first plate starting clockwise from the table head is set just about where you can feel the leg of the table, and that gets you started. Once you have the proper spacing, you can go round the entire table, plates first, then arranging all the silverware and glasses, then the butter dish and a few other things in the middle, and make sure the tablecloth isn't wrinkled, if you're using one. During the meal, the table head has the responsibility of placing any empty dishes on the left corner of the table, beside him. I pick it up, refill it from some larger pans, or just replace it with another prepared dish, always placing it on the right, whereupon he passes it down to who ever wanted it. If the same dish comes back again, I refill it a little less, unless there is some special request.
Really, folks, this is pretty mundane stuff, but if you get a kick out of it, there's a lot more where it came from.