Chuck - Gedanate is just sweet from my experience with judoka as well, especially if one maintains posture to avoid being held onto as the judoka gets launched
Did one this week at a seminar I did in Canada.
When not playing under pure Judo rules, a nice setup for a kotegaeshi works extremely well just as the judoka is about to grasp your gi
All they know is they tried for a kuzushi and the next thing they see is ceiling
Timing is everything.
Shomen ate works best for me when I can get the judoka's chin/head extended backward (body locked out with arms extended as they grab my gi) just before a very deep and sinking irimi. Again, keeping posture and sinking weight is important to not get taken to the floor - they just snap off as the weight of their own falling body breaks their grip on the gi as your back stays perfectly straight.
Like Peter says though, timing is KEY to all of this.
Just my 2 cents.