"The "main" energizers would be where the crystals are as they would handle all the high-powered energy transfer while the auxiliary or emergency energizers would lack the extra buffering and load capacity of the "mains"."
I'm aware of your theory but find myself unable to concur:
SCOTT: I've got bad news, Captain. The entire dilithium crystal converter assembly is fused. No chance of repair. It's completely unusable.
KIRK: No chance of restoring warp drive?
SCOTT: Not without dilithium crystals. We can't even generate enough power to fire our weapons.
SCOTT: Our shields will hold for a few passes, but without the matter-antimatter reactor, we've no chance.
These lines from "Elaan of Troyius" suggest that you can have deflector shields, capable of withstanding Klingon disruptor blasts, whose energy either comes from the matter-antimatter reactor together with the dilithium crystals ("warp power to the shields") or
from the main energizers.
The odd thing is that Scotty feels unable to generate phaser power, as he apparently was capable to "charge" the phaser bank of the Constellation
without the availability of "warp power" (or he is just being insubordinate, feeling that deflector shield power has priority over phaser capability