I really don't understand why anyone worries about getting estrogen too low.
Besides the fact it's really difficult for this to happen when you're taking large amounts of aromatizing AAS there is a simple way to handle this:
Start at a low dose... say 1.25mg E3D. If you start to bloat or feel symptoms of gyno up to 1.25mg EOD. Simple- start low, see how you react, and adjust accordingly.