Changing over to Charlotte Mason

I’ve been homeschooling for a few years now.  My oldest is 10.  We are just now switching over to a Charlotte Mason way of learning and I’m very excited.  I really love the Simply Charlotte Mason curriculum.  We are currently using their history and science and plan on sticking with those pretty much forever!  I’m now looking into their Language Arts.  My 10 year old is a bit behind in reading(we think he has dyslexia, but have not had him tested), but seems to understand grammar rather well.  We’ve been using First Language Lessons for the Well Trained Mind for the past 3 years.  So he’s finishing up Level 3 this year.  He does ok with it, but it is a lot of memorizing and that’s a bit tough for him.  I do like them a lot, but thinking of switching over to Using Language Well.  We have not done spelling yet, since reading has been such a struggle.  So I understand I need the Spelling Wisdom to go along with that.  My question is where do I start?  Do I start him off in 5th grade with book 1 from the series and then do book 2 for 6th grade.  I’m not overly concerned with him staying “on track” but as always, I worry about not giving him enough.   And another question, I have a 6 year old I plan on doing some things with next year, what grade do you typically start the Using Language Well in?  I’m only doing History and Science with him because we do it as a family.  Next year we’re going full on Charlotte Mason and doing picture study, hymn study, and poetry.  Any tips or help with the whole switch over would be greatly appreciated!