I'm not sure what you mean by the rail's making it difficult. If you are talking about the disadvantage of not being able to use the rail with a spinner to land the fish, I have never encountered a large enough fish while jigging to have to do that. If you mean just the jigging itself, on one trip, I jigged for a brief time (say, an hour with each) and I did not find it difficult because of the rail with either rig. I did find it more difficult to achieve hookups on blackfin using a Smith Nirai/Stella 20K though and when I switched to a friend's conventional (OTI300/Ocean Jigger) I hooked up fairly quickly. I realize one can learn to detect hits while dropping on the spinning rig, but from my scant experience, it is not as automatic.
But that has nothing to do with your question about the rail.
Russ