Please allow me to interject my 3rd person impartiality on the subject of crobars. I've only designed one but it might interest you.
The application was for a braking unit for a 20HP 480V three phase induction motor drive. The brake is a transistor in series with a braking resistor which is placed across the DC bus. When the buss voltage goes up due to the motor regenerating, the transistor turns on and the bus voltage is clamped into the brake resistor. If for any reason the brake stays on for too long then there is a good chance of a fire developing. If the brake transistor shorts there must be an alternate means to remove the bus voltage. A latching contactor on the input side would work, but is expensive to implement.
I used a 90amp SCR module in order to crowbar the bus. The bus was
1000uF at about 700VDC. So the little 90amp scr took the bus voltage down to zero, and also cleared a pair of JJS-60 fuses. And the little scr remained intact to crowbar again if needed. I don;t remember all of the details as it was over 20 years ago, but one factoid I remember is that the currents got up around 7000AMPS! And there was a fairly loud Ker-Chunk noise and the wiring did jump a little .So the point I want to make here is that you might be surprised what kind of punishment a little TO-220 scr might take. The only advice I can give you is when it's time to crowbar don't be shy with the gate drive current. Use a tight loop and hit it hard.
regards, Yzordderrex