I am having the same thoughts. I bought a BE during the annual sale without a net. I also have two HH with the zippers. I just purchased a SS Undercover, when I put it on the BE it did not seem to seal well, I do not trust it to keep me dry.
I am concerned that the UC will not keep the rain out. I hang on the coast a lot, the rain come from every direction. Not too sure how the Undercover is going to work out. I guess I will know by tonight, since we are off on another adventure. I have both types of hammocks, BE and SE, so I do not want to have anything sewn shut.
I am thinking about making a clone, selling the SS and just using the clone that I might construct. However, I will be getting into too much gear, too many choices.