I have just been experimenting with harmonising the major scale with the alternating major6/dim7 harmony as described in the podcast. Rather than inserting an extra note so that the scale starts and finishes on a consonant 6th sound why not harmonise both the 6th and 7th degrees with a dim7? Wouldn't a technique to harmonise the major scale be more practical than one to harmonise the major scale with an added note? What do you think of the sound?

That sounds good but I think that in the end it's a question of context. A lot of tunes may just have only some adjacent notes of the major scale:

5 notes descending in Fly me to the Moon with the first chord harmonised as minor

4 notes ascending in All of You with first chord either minor or major

etc

Paul