I think signing up for the Eidies would be a wise investment. How cool that they are local to you.
From reading the Eidies book, I've worked out this 'whole brain' way to get spellings into my visual working memory, which is very weak at seeing details: http://wp.me/p2tcDf-8b

Something similar might help with keeping those 'u's from rotating into 'n's.

I like the idea of a little hothousing....maybe some of the Handwritting wiithout tears preschool 3d materials like Matt Man?
Hugs
Grinity

Coaching available, at SchoolSuccessSolutions.com