Unless you have huge level fluctuations, our subfloat/counterweight method works well and requires no adjustment. We use screw anchors, but anything suitable to your bottom works, then a rope up to the subfloat, with a counterweight that has adequate length to self-adjust to expected water level fluctuations, then just clip the buoy on (with a string or zip tie as a fuseable link). Getting the weight and buoy inflation correct to float them at the proper level is critical, but we have one course that has ropes 20+ years old and one that's about 10 and there's negligible wear between the subs and weights. My brother used to ski at a site that had massive anchors and really heavy chain up to their subfloats which were aluminum buoys. Above that their system was more or less breakaway, but from the bottom to subs, it was pretty much indestructable.