Of course you will read different opinions, as we all have our own experiences. Hey, that's OK.
First off, I would do the topping off with brandy. This port will be very thin, compared to a commercial port. I would add at least 2 bottles of brandy to this 6 gallons of port. It will improve the taste, the ABV, and give it a much better mouth-feel (body).
A port is usually higher alcohol than you will get with this port "as-is", so the brandy will make it more port-like. As a matter of fact, you can easily add 3 to 4 bottles and it will be even better, but I wouldn't do that the first time.
I think you said your wife didn't like brandy to be added, so that's OK; just be ready for a thin, low alcohol port, which is still going to be very nice.
It will be a much better port in a year and very nice in two.
Whatever you do, have fun with this.