Only skimmed through the beginning of the grammar section, and it looks more technical than most of what I've seen so far online.
I must say that after I had studied Japanese for some time, reading Reiko Shimamori's systematic japanese grammar (Grammaire Japonaise Systématique, actually, I don't think there's an english edition of this french book) was an eye opener. Japanese grammar made so much more sense to me once I heard about 連体形, 未然形, etc. And I'm glad you talk about those. As I said, though, I only skimmed, but a quick search doesn't reveal any mention of 助動詞, sadly.
PS: the menu on the right overlaps with the text if the window is narrow, and that makes it impossible to read.
I must say that after I had studied Japanese for some time, reading Reiko Shimamori's systematic japanese grammar (Grammaire Japonaise Systématique, actually, I don't think there's an english edition of this french book) was an eye opener. Japanese grammar made so much more sense to me once I heard about 連体形, 未然形, etc. And I'm glad you talk about those. As I said, though, I only skimmed, but a quick search doesn't reveal any mention of 助動詞, sadly.
PS: the menu on the right overlaps with the text if the window is narrow, and that makes it impossible to read.