I don't think that you (we) are going to easily find any single E6 film similar to K64, maybe because the dyes forming the image in K14 are of a totally different chemical nature to those in E6?

Whereas those in the different types and makes of E6 are presumably much more similar, with the differences between the films being those which the manufacturers choose to "build in" in fine-tuning the different emulsions?

If my theory is correct, it is perhaps going to be a case of we Kodachrome users just finding an E6 film with characteristics which we like, rather than trying to replicate Kodachrome....in which case possible choices have been suggested in several previous threads.