Hi Mech, thanks for your reply!
the thing is I’ve got a brand new crank and there’s no marks on either of them where stated, but the balancer has to be in time with the crank correctly or a: it wouldn’t cancel the vibrations it’s designed to and b: it hits the crankshaft web and journal, the web is clearanced to allow the balance weight to pass . I’d assume with the crank at TDC the balancer would be centrally in the crank web and opposed at BDC, but assuming can be dangerous lol.
have a great day!