I use the Felder 90 degree connector for my A3 and my saw/shaper. No need to reinvent the wheel, the connector fits perfectly and is easy to slip on...
The short circuit current on a 50 ampere circuit will be somewhere around 20 times rated current (depending upon the circuit and fault impedance), so...
I've been looking for myself and have pretty much settled on this model. It's currently on sale for $329 at Lowes and features the front slide rails...