Which version of the game is? Does it have Act I and Act II included?
Is this still the recommended way of playing? Doing the 18+, then skipping all the all ages, the play side story, rinse and repeat?Best way is to do the routes following the walkthrough at fuwanovel.
Start first route (Kasumi) in 18+ to get the h-scenes and play till end of route, then start up the all ages version and just skip through the same route (f7 instant skip to next choice), straight till end so you unlock the sidestories.
Read sidestories in order as they appear in the walkthrough.
Start second route (Kei) 18+ rinse and repeat.
Only extra in girl route in the all ages version is the second Rhea route, this is made by another writer.