Not sure about those plastic snaphooks... I just had a big scare with a plastic hook breaking on a neckstrap (see my other posting). To me the best strap for a sax case is the one made by BAM. Metal lockable carabiner hooks, padded over the shoulders.
It's available on Amazon for example: https://www.amazon.com/Instrument-Case-Strap-Bam-France/dp/B00114VCHE/ref=sr_1_2
It's available on Amazon for example: https://www.amazon.com/Instrument-Case-Strap-Bam-France/dp/B00114VCHE/ref=sr_1_2