I think I may need to get a rope with a higher safe load limit
That rope is fine. It's not the
tensile strength that is indicated there. The tensile strength and the
safe working load are two different things. The tensile strength of this rope is probably somewhere between 240 and 420 kg (or 4x to 7x the safe working load). The safe working load is the weight that the rope can be safely used with under normal operation.
Of course, you can get a stronger one, but it's not necessary.
For full suspension can padding be used? I don't want to compress my trachea if I can to avoid SI. Any tips or advice would be greatly appreciated.
Personally, I wouldn't use padding. I would be afraid that it shifts out of position, or that I do it incorrectly, in which case it does more harm than good. I don't think padding is necessary. If you don't want to compress your trachea, place the rope above the Adam's apple, below the jawline. The trachea goes from the voice box (larynx) down to the lungs.