Forgive the self promotion - not the intention. But here is said bass in action on some tracks.
https://soundcloud.com/glowrogues/theallnightlights
https://soundcloud.com/glowrogues/gloaming
http://xotic.us/guitars/xj1_5st/xj1_5st.html
According to the site, around the 4.5kg mark. It's got some weight to it! Reassuringly so, but obviously not for those who need to look after their backs