Garboard Drain for E-27?

I am currently working to restore my '73 E-27 to Bristol shape. I have not yet gotten all of the fittings replaced/rebedded. Thus water accumulates rapidly in the bilge. (Time/weather not co-ordinating with budget). A friend suggested installing a garboard drain in the area aft of the keel. I am in the process of repairing a 'leak' where the cutlass bearing used to be , so I am a little sensitive to adding a non-OEM hole in the hull, let alone in a location well below the waterline. Your thoughts appreciated as I am 1/8th complete on barrier coating the hull.

My E29 has a garboard plug installed in the lower part of the keel well. It was installed by the previous owner who told me he did so to allow a better flushing of the bilge in the off season. The factory installed maual bilge pump does leave about a foot and a half of water in the well. In August the bilge gets that familiar icebox smell (icebox drains to bilge) but I don't know what the bilge would be like if it wasn't flushed in the off season. It does help with winterizing the boat. It is my understanding that the plug was installed using some kind of a horizontal boring device from the inside of the keel well. I can't verify the installation method, that's just what the previous owner told me.

Bilge pumping

I use a portable hand bilge pump if I want to get the well almost completely dry. I would be hesitant to put a hole in the well.