Marrow Lockdowns?

Does anyone have any viable lockdowns for Marrow(A)/Doom(B)/Tron©? I had been using c.lp > c.lk + tron > s.lk > s.fp(or rk) X Bonerang but people are able to escape that too easily. that goes double for using Doom. Any ideas on what I could do differently in terms of lockdown/blockstrings?