454 SRH = 0.310
44 SRH = 0.332
480 SRH = 0.390
IIRC, I used the .390" front with my ORH rear on my .41 Mag SBH Bisley Hunter. If using a standard notch rear I would try one size lower. If in doubt, call Marble's, Troy gave me the height recomendation and it was perfect. Green works the best, IMO, for all-around conditions.