The best mounting system is the Ortleib/Rixen and Kaul style with QR locking hooks and a sliding rail and a lower solid hook on a rail.
Hook and elastic are 1970s technology and can bounce off.
The QR hooks with a lower strap require some manual fiddling when you attach the bags. It may only take a couple of seconds but there is no fiddling with solid anti-sway hooks. If you remove your bags several times a day, messing around with dirty bags becomes very old.
Beware of cheap QR hooks where the hook is not one piece but has a pivot at the topmost part. If/when the hinge fails, the hook no longer grabs. The bag will pivot down into your wheel.

Shorter chainstays require a bag with a heel cutout profile.