If you're used to playing P basses, a dual J may be either a revelation or a disappointment at first. Either case it may take some time to recalibrate your ears and get used to how that set up reacts to your playing and sounds. As other have said, B string is as about solid as it gets. Regarding the string spacing, you'll have to see for yourself. I wish I could tell you one way or the other but it's such a personal preference. I've tried 19mm spacing a number of times and decided it doesn't work for me on a 5 string. I prefer a tighter string spacing on 5 strings, somewhere around 17-18mm. I know that sounds subjective but its something that I realized over time.
Regarding weight, as Lomo said, if you're ordering a USA model then that should be something you can request. Otherwise, it's a crap shoot. I've seen/played Skylines that are super light and some that have the density of dying star. As far as color goes, if you're going with blue, look into their ice blue metallic. I don't typically gravitate towards blue but I have this on my 44-60 and love this color. The metallic is subtle and there are elements of silver in there. Under certain lighting different hues pop out a bit.
Otherwise very exciting. Good luck and let us know what you decide.
