More on water levels...
I am not sure why I didn't think of this earlier, but most of the owner's manuals I've been collecting for the early through late 1960s Kenmores mention in the controls section how much water is going to be provided with each fill level on the water level switch when the machine has a selectable switch.
LO is usually 11 gallons, MEDIUM being 14 gallons, and HI being 18 gallons. This was so nearly universal in these various manuals that I considered that a common setting in all the 29-inch standard capacity machines until I saw that Kenmore service letter to the field. Machines that had only one level filled to 18 gallons. Machines that had two were usually 11 and 18 gallon settings. Machines that were infinite were selectable anywhere between 11 and 18 gallons. See a trend there?
In 1978/1979 max fill dropped to 17 gallons, probably to tweak the rating on the yellow energy guide. The other settings didn't change.
Being that the tub is full at 18 gallons, which I think is about an inch below the rim on the inside of the wash basket, an 11-gallon LO setting would would be pretty much right at the 2/3 full mark.
One thing I've noticed, and we found it out first-hand with Andy's beautiful '66 Lady Kenmore at the April Wash-In - his level switch, set to the lowest of LO, had the tub 3/4 full or more and still going, and we started to be concerned that the machine would overflow. It didn't, but obviously the switch was not functioning properly. I think after several fills and tweaking of the switch, it was working better. We decided that after a long period of non-use, it had become in-accurate or 'stuck'. I've had the opposite happen, where machines fail to fill all the way, and as time goes on, they fill several inches lower than they did originally.
G