We do Spell to Write and Read which uses the Spalding method. I am not an expert, just from doing it with my DD over the last year and starting with my DS this year.
For my DD the physical connection of making the notations helps the rules make sense in reading and also writing. Instead of just looking at a card and knowing the rules, the act of writing those notations really helps the rules “stick”. She only does notations for the actual spelling lists, not in every day copy work or writing. It really helps her read as well, with the sounding out words. Knowing when a silent E is silent, or when seeing “the” that the “th” together says a certain sound.
Have you read about the Spalding method – many times The Writing Road to Reading is available at the library. If you understand how the rules work, teaching them makes a lot more sense. My mom taught my siblings and I with The Writing Road to Reading so while it took me a while to really remember all the rules, it has hellped me with spelling as an adult as well.