I looked at the available duo strap options and decided they were too fiddly and expensive so I created my own. I just use two standard straps, each fastened to the bass independently with Schaller locks. The first strap is in the standard position on the left shoulder and fastens onto the usual buttons … no change there. The second strap fastens onto a new button on the top horn (alongside the existing one), goes over the right shoulder and fastens onto a new button on the lower horn. The strap lengths are adjusted so that the weight feels even on both shoulders. The bass is now in the ideal playing position, feels half the weight and has zero neck dive. My neck and back feel much better and my technique has improved from not having to “hold” the bass at all. It’s a cheap and simple DIY system which just snaps on/off. Thought I’d share in the interest of helping others currently wrestling with this issue.