This is my tip for gluing on a long keel.
Drill small holes in the keel just big enough to insert some small pins.
Tape the keel in place, tap the pins to make a mark.
Remove the keel,then push the pins in so That they show through The underside.
Apply the glue to the underside of the keel,line up the pins with the pin marks then push the keel down the pins on to the hull.
When dry Remove pins and fill pinholes.
It might help.