Supplemental readings to go with D'Ooge; Lingua Latina?

Textbooks Latin For Beginners by D'Ooge
1

All, I’ve been studying Latin with my homeschooled son for several years, but at a very basic introductory level. We’ve just started D’Ooge’s “Latin for Beginners” and it seems to be going well. We like D’Ooge. I thought it would be a good idea to do some supplemental readings; I’ve seen that recommended, anyway.

My basic question is: supposing we want to start a book of supplemental readings either now, or not long into our study of D’Ooge, what would you recommend?

In particular, I wonder if anyone can confirm that studying “Lingua Latina per se Illustrata” alongside D’Ooge is a good idea. Are they well matched? Is “Lingua Latina” more advanced than D’Ooge? Will it be possible to understand “Lingua Latina” if we just read D’Ooge and that, and nothing else? We have no trouble whatsoever understanding the first several pages of “Lingua Latina.”

I was also looking at the “absolute beginner” readers “Cornelia” and “Carolus et Maria”—both looked easy enough, but I’m wondering if we wouldn’t be better off just getting “Lingua Latina.” I don’t care about the $25 “Lingua Latina” will cost. The main question is which would be best for a bright elementary student who has already studied some basic Latin.

2

How old is your son? I guess you both are at the same level of Latin?

3

I didn’t notice the question until now—didn’t subscribe.

He’s 8. He also knows his mother’s language which is inflected and we’ve been studying Latin casually since he was 4 (using e.g. Rosetta Stone and Linney’s Getting Started with Latin. My son and I are about equally matched in Latin ability, but I’ve studied several languages before, including Greek, so I think I have a leg up on him.

Anyway, we’re now on p. 28 of D’Ooge and have started working through Julia by Maud Reed. But I’ve also printed out the first 10 pages of several other books and I’m still very curious whether anyone else has used Lingua Latina with D’Ooge and can say if they’re well matched, or if Lingua Latina is going to require a teacher who knows Latin (not me, obviously).