I'm not sure what a "garnet" finish is but . . . I always seal ptnr (or any rush seat) with a 50/50 mixture of 3 lb cut shellac and denatured alcohol. Once dry a stain can be applied, or a stain can be added to a 2nd coat of 3 lb cut shellac (not thinned). With a final clear 3 lb cut shellac coat to either seal the stain so it doesn't color clothing when the seat is used, or to give a finish to the new seat. Hope this helps.
I'm not sure what a "garnet" finish is but . . . I always seal ptnr (or any rush seat) with a 50/50 mixture of 3 lb cut shellac and denatured alcohol. Once dry a stain can be applied, or a stain can be added to a 2nd coat of 3 lb cut shellac (not thinned). With a final clear 3 lb cut shellac coat to either seal the stain so it doesn't color clothing when the seat is used, or to give a finish to the new seat. Hope this helps.