Sometimes former have to be just used as guides. You make a thick glue set up, and apply to the former. Try then to apply your perfect shape disc, and peel it back, to peek in there and see how the glue is touching the former and saucer (hull, whatever), if it isn't touching, but the glue is, just let is dry, as long as it dries with the disc in shape touching, your good to go. I have found in ship modeling that a former can really destroy the shape of the Hull. On certain models, I make the hull first, then make sure it is symmetric, then slip for former frame into it. I trim or add as necessary, when satisfied that the frame fits in nice, without any force, I glue in place. Gaps won't matter as the glue getting hard will give you the support you need. At this stage you can add "L" pieces to put support where you think you made need it.