I run my rudder on the right as with most monos, it still turns left ok.
You will not get a surface drive boat to turn equally well both ways as the prop walk will always make it turn better right.
A rudder directly behind a surface drive propwill cause a lot of drag and will not be as effective as one off to the right.
Usually rudders are sited so the leading edge is about inline with the drive dog, there are variations to this guide but as a first buildI suggest you stay inside the ballpark.