Modules 1 – 4 cover the fundamentals of playing. That information is interchangeable between either tuning. Module 5 & 6 contain the performance tunes. The 3 songs in module 5 should work fine for low G. The same goes for the first song in module 6, but the last 2 might have some “off” sounding notes when using a low G.
I’d keep the low G and jump in! Hope you enjoy the lessons and if you ever need help on them or have questions, please don’t hesitate to ask 🙂