I agree with the others in that you don't need a topshot when float fishing.

However, if you ever do need to go braid to mono the two go-to knots are the Albright and FG knot. Albright is simple and clean through the guides. FG is complicated but slimmest knot there is and also the strongest. Albright will suffice for any kind of salmon fishing we do around here though.

Uni to uni.... sucks!