As noted, it was noted in the book Production for the Graphic Designer by James Craig that a weakness of the Selectric Composer is that there were only three escapements, covering a wide range of point sizes. So both 9 and 10 point type might use the 1/84" escapement, and thus changing from 10 point type to 9 point type might not save as much space as expected.
Although all the escapement sizes on the Selectric Composer were fractions of 1/12", tabs on the Selectric Composer could be set only at intervals of 1/6". This suggests that intermediate escapement sizes of 1/78" (orange) and 1/90" (green) could be added. This change would also be trivial.
And, since a 1/60" escapement was suggested as an addition on the previous change, presumably a 1/66" (purple) escapement would also be added at the same time. As there were 11-pitch typefaces available for the IBM Executive typewriter, as a compromise between Pica and Elite, this would enable the typewriter to handle those.
Another feature already present in the IBM Electric Composer was the ability to switch to a different allocation of units to some positions on the keyboard, so that a dual-case Copperplate Gothic element could include capital letters in a smaller size as its lower case.
A useful option of a similar type would be another alternate unit allocation, in which the lower-case letters would retain their usual spacing, and the corresponding upper-case positions would have similar widths on a smaller scale, so that an element could contain both lower-case letters and superscript lower-case letters. This would be particularly useful on an element with italic type, for typing mathematical formulas, but one with normal type would also be useful, for example, for function names.
The Symbol Greek element positioned Greek letters on the keyboard so that they would be replacing letters of the Latin alphabet with the same width. Therefore, following the same arrangement, this alternate spacing could also be used for an element with Greek letters in lower-case and superscript lower-case forms.
Thus, comparing the spacing of the Selectric Composer normally with that for the double case Copperplate Gothic element, and for one that offered superscripts, one has the table below:
Normal 3 ijl .,;`'- 4 ftrs I :!()/ 5 acegz J [? 6 bdhknopquvxy PS 0123456789 ]+*=$† 7 BCEFLTZ 8 w ADGHKNOQRUVXY &@%½¼¾ <em dash> 9 m WM Double-Case Small Capitals Other 3 I .,;`'- 4 J 0123456789 I :!()/ 5 LPSTZ J [? 6 ABCDEFGHKNOQRUVXY PS ]+*=$† 7 MW BCEFLTZ 8 ADGHKNOQRUVXY &@%½¼¾ <em dash> 9 WM Superscript Superscripts Other 2 ijl 3 ftrs () ijl .,;`' 4 abcdeghknopquvxyz 0123456789 +-= ftrs :() 5 w acegz 6 m bdhknpquvxy 0123456789 +-= 7 8 w 9 m
Since the superscript numerals would be placed as the shifts of the regular numerals, the regular +, (, and ), which it is desired to keep, would need to be placed on other keys, and, as well, superscript versions of those characters would be added. So the fractions, the square brackets, and the question mark are additionally shown as removed.