CR729 Very reddish brown, semi matt with darker spots

Rather thick or it will be no spots. 1260-1280oC with one hour at the top temperature. One of the most red glazes I know based on ferric oxide in oxidation. You can try other simple boric frits with not too low maturing temperature instead of G-3.
glaze CR729, small bowl feldspar NGP 37,22
bone ash 12,41
talc 8,68
petalite 12,41
quartz (flint) 9,93
ball clay 7,44
red ferric oxide 6,95
borax frit MOK G-3 4,96