Thinkin about haveing mine covered and seeing if they can stiffen up the sides to hold me in better.
This can be done!
But it's just not a matter of gluing some foam on top of what's there already.
The factory foam has to be sliced open on the sides, front to back, then a wedge of 'rebond' foam glued inside of the sliced factory stuff. This will raise & firm up the outer edges to hold you in the seat better, but it will retain the original shape, more or less, along with the original feel of initial comfort of the seat.
The wedges in the cushion taper from small to large, from the center to the outer edges.
The backrests are more of a compound taper. The will have the same taper as the cushions, but will also taper small to large, top to bottom.
If the foam wedges are glued on top of the existing foam, not only will it eventually shift around inside the cover, but it will not feel right to sit in, especially for any length of time. I learned to do side bolster build ups like this years ago. I hate having my jobs come back to me for a repair on something I did. I don't get paid to do it a second time!
'Rebond' foam looks like carpet underlay. A bunch of foam chips glued together. Comes in different thicknesses up to 4" thick, & in different densities.
Usually a new set of covers has to be made to fit the new shape of the foam.
I really wish that I lived closer to more of you guys. I just hate to see good money spent on a half-assed job.