Since no-one seems to be bothered to look at the 'technical' section, I shall re-post my idea into this forum:

I always had slight difficulty typing a whole bunch of words in the cmk lessons, which contained two newly introduced letters that were both on the same row (excluding home row letters). For example the lesson that introduces F and U (#6) makes me mix up both keys frequently (during the lesson only).  Therefore, I have made an alternative lesson–that would be lesson 5–for V and L, to try how it compares. What do you think?

toil lithe vivid oiled less live sold vent lever slid levee dive slat slit
raven vain hall naval oven valet voodoo still lotto vet dial hill land
oven vote lead vain solid shave saver old lone vie ale nill novella loose
evident let vale have alone eve volt lost navel line vase vole last vane elusive
install love sole tall vista total dove loot save devil vile venal stilton lilo
vote lot vole even loads loan levels vernon several novel varies sensitive relative hold