I tried your suggestion connectPerim' arrowStyle "prior" "ssa" (0 @@ deg) (180 @@ deg)
I also tried connectPerim' arrowStyleU "prior" "ssa" (0 @@ deg) (180 @@ deg)
As in the pictures below, both don't give desirable results.
Sorry if my question was not clear. What I want is to make the reverse "Z" looking arrow straight and its head placed below bandpass-ssa arrow. Thanks for the help.