I do something very similar. I do interface -> open crate also. And either an EU item node with a filter to pick up the finished seeds, or a botania hopperhock next to a chest with item frames that contain the finished items to act as the filter (you don't need to power the hopperhock with mana, its range is good enough without). To turn on /off the accelerators, I use multiple level emitters with a crafting card upgrade in them, so they emit redstone when that item is being crafted by the system. Then just redstone from emitters to a toggle bus to turn on / off the power.