KM, never liked the adapter plates for Fogmans. Just never felt this would be precise enough. Once I wanted to quickly try out a ski w plates and lost it in the middle of the pull/boat wake. Still hurts when I remember. One piece thin G-10(I think) plate for RUs, fixed with Dual Lock to the ski seems to be what works best. Used to drill RUs directly in the ski (80% Goode skis), never had issues, aside for resale value. Still waiting to try out the Fogman thick G-10 plate as described by clemsondave. Thinking about experimenting with different boots (Reflex, powershells). Would like a stiffer, taller front and a flexible, lower rear boot to save the achilles. Feet, of course, need to stay together no matter what...
Regarding your concern of losing the adapter plate(plates?), I always had only one release, either the Fogman itself or the whole plate with Fogmans on it. I guess theoretically it could happen that the plate & RUs sink if they separate!