Question about Foundation One training integration

I've been doing a self-guided GB workout for awhile from Coach Sommer's original book "Building The Gymnastic Body", which doesn't have nearly the amount of detail as the online Foundation One (F1) series.

As a result of my own training from the book, I can do the MU, SL, 1/2 FL, HSPu, and bulgarian ring dips confidently.

I recently started the FI series and I'm still on PE1 for most of the exercises. So far it's going OK and the iM stuff is a big help. That said, seeing as I can already do some of the more difficult moves above that aren't covered in the Foundation series, can anyone make a recommendation as to how to integrate them into my F1 training? Basically I don't want to "lose" those skills while I'm training to learn new ones, but I also don't want to tire myself out doing the harder skills and hold up my progress in the Foundation series. 

Any input would be appreciated. Thanks. 

Do your foundation work first each workout. After you have completed your foundation work for the day, feel free to do some light volume work to maintain your skills, but don't tire yourself out too much.

Thanks, that makes sense; I'll try to fit it in on days off or afterwards if I'm still fresh. 

This should really be in the FAQ...