Geoff,
Have you considered using waterproof double sided tape? Bryan Young on here used it extensively and successfully on his working models. It comes in all sizes and in different thickness levels to accommodate differeing levels of substrate. After all, its what they use to stick bits on cars. I don't think there is any likelihood of it coming off, especially when overpainted as well.
Just Google waterproof double sided tape and all sorts of options come up.
When fixing you can apply it to each plate individually, cut round it with a scalpel and thn carefully peel off the backing - you do need to get it positioned correctly though as once it is on and pressed down it will be the devil to remove - but then that also applies to cyano which is a lot messier to use. Essentially you are creating self adhesive plates, probably a much nicer way of doing the job.
Colin