Carb spacers arent nececelery, there more of a tuning aid and to keep the fuel charge cooler. If your going for a dual plain intake, then a divided spacer, or 4 holer would be good, but if your going with a single plain intake, go for an open spacer. Its basically a test and see what you like theory of spacers basically. If your linkage hits, or any other interference, then spacers help, or if you cant get a good idle on your carb, then spacer may help. There's so many types, sizes, and compositions of spacers out know and Im not real knowldegable on them all, so I'll leave the rest to someone else to recommend a certain one.
