Too much brake fluid?

Can one have too much brake fluid in the coffin style reservoir? I had installed some EBC "green"backs last year on the quick and cheap prior to a trackday. The pads were marginal but served their purpose before they just dusted themselves out of existence.
I'd probably bled and topped off the brake MC in hopes of getting a little better braking action. NOW, I installed EBC HH, which I had been pretty happy with in the past. (SS galfer floaters).
The new pads were dragging on the rotors. I rechecked my installation and was satisfied mechanically that nothing was improper. I then peeked into the reservoir, and it was pretty well crammed full after having put full thickness pads in place of the old worn ones. I removed a small but noticeable amount of fluid and sealed it back up.
There is somewhat less drag on the pads now, but I have to wonder, is there such a thing as too full a MC reservoir?

Yes, you can have too much. When the pads heat up, the fluid expands and the excess goes into the reservoir. If the reservoir is full the fluid exerts pressure on the pads and drags on the discs.

Very common problem when folks put in new pads. If the fluid was changed or topped up with old pads the new ones will fill the res. this can cause the brakes to drag from air pressure if your lucky and in the worst case, the calipers heat, expanding the fluid, making more pressure, making more heat and next thing you know, your doing a stoppie. Check this when changing pads.