I used tape with great success. In the past I had used proseal and worked great but messy work. The tape, if you have not seen it, is extremely thin and occupies less space than proseal and I personally don't see any concern for moisture retention/corrosion. But I had primed all my surfaces.
N825SM RV7A - IO360M1B - SOLD
N825MS RV14A - IO390 - Flying