Photos and text courtesy of Ian Freeman, Pearl City.
1. Create a template using a piece of wood, with the guide hole in the middle and two securing screws on either side of the soffit vent.
2. I went with 2 3/4″ holes, and a good quality Milwaukee holesaw, holesaw mandrel and heavy duty 1/2″ chuck industrial drill. Battery kine drill may get thru one hole per battery charge.
3. Cover the holes behind with one rectangular piece of 1/4″ galvanized mesh wire and staple it in place with galvanized or stainless staples, then paint inside your new holes and a dab of caulk in each screw hole.