I tested it some more and it was fine.
The only issue that sometimes happens, usually with the duck, is a difficulty in buffing a major slip - a minor comes out instead. But this oculd be just about getting used to it. I read someone else commenting this, so maybe it's a thing.
Another thing to consider that if you buff a minor slip and your press the punch input very quickly, it will override the slip. If you do 1-minor side slip-2, you end up throwing a 1-2. You can still sort of time it to get it right, but maybe something could be done to facilitate the inputs.
However, buffing minor slips themselves, seems like the easiest thing.