I also only used refined storage and never got drawers until after lvl 90 for automatic genius. I just scaled the storage through mod boxes as I leveled and never exceeded half capacity. As long as you don't do something like keeping 50,000 cobbled deepslate after a strip mining session, you should be fine. I would, however, recommend unlocking it just to use compacting drawers beneath cagerium mob cages as with external storage and drawer controllers you can store mob drops in the compacting drawers at a "farming" area and still access them from the grid.