I wouldn't bolt the axle down till it was completed, hooked up to your bike and loaded to the 480 lbs. (including cooler ice and favorite adult beverages)
The distance from the center of tongue to center of axle must be at least 1.5 times the axle width. (if memory serves me),easy enough to check , there's a lot of info on trailers on internet.
Agree the further back the axle is, the more stable a load is, BUT, it will also put more weight on your bike.
An RSV has a limit of 45 LBS? tongue weight so you may have to move the axle forward(but not past the minimum stated above) to allow the trailer carry most of the load.
Whats a Goldwings limit?
Maiden voyage should be behind a pickup truck with tail gate down. That way you can test the old girl out before you put your a$$ on the line..LOL AKA less of a pucker factor... Good Luck!
P.S. Remember, there's a reason they call it the bleeding edge, Be SAFE...