RE: looking for advice buying a new board
I am 78kg and the 133 is OK to uphaul and will take a 9.0 sail. As your partner is 90kg and you are looking for a little more volume, then the 144 might be more suitable for you. It will plane quicker but is still fast and fun.
The Go is a good board; but people who have bought them at our club soon grow out of them and want something with a little more "zing!"