You have to get the special cusions for those injectors. The only difference between the ve ports and de ports is the oem cusion size. The bore should be identical. They make the id1000 injectors specifically for the SR motor. The part where the o-ring is is different and is actually non existent. The tip is different, it goes around the cusion and the start of the silver part above the o-ring in the picture is what seats against the custion.
You can see what i mean there. These injectors had no lower o-ring.
By what your describing your better off to purely use the oring seal and bore the manifold out to fit the o-ring. The o-ring seal is more than enough to seal it. Ive been using purely o-ring seal on my new manifold and its never had issues. No seats or cusions.