Hi Neil! I recently used SP on buffered formalin perfused rat and guinea pig. Peninsula T-4106 1 : 250 in PBS + 0.1% BSA + 0.025% Tween 20 60 mins. Swine anti rabbit 1: 150 in that PBS 60 mins. ABC in normal PBS 30 mins. Aliquotted DAB 50 secs. Mike.