Get some sliding d rings online and put them on the waist belt/strap. Me personally I believe you are overweight because of how much air you have in you’re BC. It would not hurt getting a “sidemount refresher” just to be even more prepared for you’re cave course. I will say in 10 years sidemount has exponentially grown. It might be time for an upgrade. I personally run the XDeep harnes with the Tec bladder and I absolutely love it. I have tried 2 other systems and I personally found that Xdeep fits my style of diving. I also would recommend staying away from a 4 inch spg hose just because it won’t give you enough flexibility for a 180 in my experience. I don’t trust the miflex hoses, seen too many of them fail.